DEFINITION ty3_sred_wcpr0_pr0()
TYPE =
       ∀g:G.∀c1:C.∀t1:T.∀t:T.(ty3 g c1 t1 t)→∀c2:C.(wcpr0 c1 c2)→∀t2:T.(pr0 t1 t2)→(ty3 g c2 t2 t)
BODY =
        assume g: G
        assume c1: C
        assume t1: T
        assume t: T
        suppose H: ty3 g c1 t1 t
          we proceed by induction on H to prove ∀c2:C.(wcpr0 c1 c2)→∀t3:T.(pr0 t1 t3)→(ty3 g c2 t3 t)
             case ty3_conv : c:C t2:T t0:T :ty3 g c t2 t0 u:T t3:T :ty3 g c u t3 H4:pc3 c t3 t2 ⇒
                the thesis becomes ∀c2:C.∀H5:(wcpr0 c c2).∀t4:T.∀H6:(pr0 u t4).(ty3 g c2 t4 t2)
                (H1) by induction hypothesis we know ∀c2:C.(wcpr0 c c2)→∀t3:T.(pr0 t2 t3)→(ty3 g c2 t3 t0)
                (H3) by induction hypothesis we know ∀c2:C.(wcpr0 c c2)→∀t4:T.(pr0 u t4)→(ty3 g c2 t4 t3)
                    assume c2: C
                    suppose H5: wcpr0 c c2
                    assume t4: T
                    suppose H6: pr0 u t4
                      (h1) 
                         by (pr0_refl .)
                         we proved pr0 t2 t2
                         by (H1 . H5 . previous)
ty3 g c2 t2 t0
                      end of h1
                      (h2) by (H3 . H5 . H6) we proved ty3 g c2 t4 t3
                      (h3) by (pc3_wcpr0 . . H5 . . H4) we proved pc3 c2 t3 t2
                      by (ty3_conv . . . . h1 . . h2 h3)
                      we proved ty3 g c2 t4 t2
∀c2:C.∀H5:(wcpr0 c c2).∀t4:T.∀H6:(pr0 u t4).(ty3 g c2 t4 t2)
             case ty3_sort : c:C m:nat ⇒
                the thesis becomes ∀c2:C.(wcpr0 c c2)→∀t2:T.∀H1:(pr0 (TSort m) t2).(ty3 g c2 t2 (TSort (next g m)))
                    assume c2: C
                    suppose : wcpr0 c c2
                    assume t2: T
                    suppose H1: pr0 (TSort m) t2
                      (h1) 
                         by (ty3_sort . . .)
ty3 g c2 (TSort m) (TSort (next g m))
                      end of h1
                      (h2) 
                         by (pr0_gen_sort . . H1)
eq T t2 (TSort m)
                      end of h2
                      by (eq_ind_r . . . h1 . h2)
                      we proved ty3 g c2 t2 (TSort (next g m))
∀c2:C.(wcpr0 c c2)→∀t2:T.∀H1:(pr0 (TSort m) t2).(ty3 g c2 t2 (TSort (next g m)))
             case ty3_abbr : n:nat c:C d:C u:T H0:getl n c (CHead d (Bind Abbr) u) t0:T :ty3 g d u t0 ⇒
                the thesis becomes ∀c2:C.∀H3:(wcpr0 c c2).∀t2:T.∀H4:(pr0 (TLRef n) t2).(ty3 g c2 t2 (lift (S n) O t0))
                (H2) by induction hypothesis we know ∀c2:C.(wcpr0 d c2)→∀t2:T.(pr0 u t2)→(ty3 g c2 t2 t0)
                    assume c2: C
                    suppose H3: wcpr0 c c2
                    assume t2: T
                    suppose H4: pr0 (TLRef n) t2
                      (h1) 
                         by (wcpr0_getl . . H3 . . . . H0)
                         we proved ex3_2 C T λe2:C.λu2:T.getl n c2 (CHead e2 (Bind Abbr) u2) λe2:C.λ:T.wcpr0 d e2 λ:C.λu2:T.pr0 u u2
                         we proceed by induction on the previous result to prove ty3 g c2 (TLRef n) (lift (S n) O t0)
                            case ex3_2_intro : x0:C x1:T H5:getl n c2 (CHead x0 (Bind Abbr) x1) H6:wcpr0 d x0 H7:pr0 u x1 ⇒
                               the thesis becomes ty3 g c2 (TLRef n) (lift (S n) O t0)
                                  by (H2 . H6 . H7)
                                  we proved ty3 g x0 x1 t0
                                  by (ty3_abbr . . . . . H5 . previous)
ty3 g c2 (TLRef n) (lift (S n) O t0)
ty3 g c2 (TLRef n) (lift (S n) O t0)
                      end of h1
                      (h2) 
                         by (pr0_gen_lref . . H4)
eq T t2 (TLRef n)
                      end of h2
                      by (eq_ind_r . . . h1 . h2)
                      we proved ty3 g c2 t2 (lift (S n) O t0)
∀c2:C.∀H3:(wcpr0 c c2).∀t2:T.∀H4:(pr0 (TLRef n) t2).(ty3 g c2 t2 (lift (S n) O t0))
             case ty3_abst : n:nat c:C d:C u:T H0:getl n c (CHead d (Bind Abst) u) t0:T :ty3 g d u t0 ⇒
                the thesis becomes ∀c2:C.∀H3:(wcpr0 c c2).∀t2:T.∀H4:(pr0 (TLRef n) t2).(ty3 g c2 t2 (lift (S n) O u))
                (H2) by induction hypothesis we know ∀c2:C.(wcpr0 d c2)→∀t2:T.(pr0 u t2)→(ty3 g c2 t2 t0)
                    assume c2: C
                    suppose H3: wcpr0 c c2
                    assume t2: T
                    suppose H4: pr0 (TLRef n) t2
                      (h1) 
                         by (wcpr0_getl . . H3 . . . . H0)
                         we proved ex3_2 C T λe2:C.λu2:T.getl n c2 (CHead e2 (Bind Abst) u2) λe2:C.λ:T.wcpr0 d e2 λ:C.λu2:T.pr0 u u2
                         we proceed by induction on the previous result to prove ty3 g c2 (TLRef n) (lift (S n) O u)
                            case ex3_2_intro : x0:C x1:T H5:getl n c2 (CHead x0 (Bind Abst) x1) H6:wcpr0 d x0 H7:pr0 u x1 ⇒
                               the thesis becomes ty3 g c2 (TLRef n) (lift (S n) O u)
                                  (h1) 
                                     (h1) 
                                        by (pr0_refl .)
                                        we proved pr0 u u
                                        by (H2 . H6 . previous)
ty3 g x0 u t0
                                     end of h1
                                     (h2) 
                                        by (getl_drop . . . . . H5)
drop (S n) O c2 x0
                                     end of h2
                                     by (ty3_lift . . . . h1 . . . h2)
ty3 g c2 (lift (S n) O u) (lift (S n) O t0)
                                  end of h1
                                  (h2) 
                                     by (H2 . H6 . H7)
                                     we proved ty3 g x0 x1 t0
                                     by (ty3_abst . . . . . H5 . previous)
ty3 g c2 (TLRef n) (lift (S n) O x1)
                                  end of h2
                                  (h3) 
                                     (h1) 
                                        by (getl_drop . . . . . H5)
drop (S n) O c2 x0
                                     end of h1
                                     (h2) 
                                        by (pr2_free . . . H7)
                                        we proved pr2 x0 u x1
                                        by (pc3_pr2_x . . . previous)
pc3 x0 x1 u
                                     end of h2
                                     by (pc3_lift . . . . h1 . . h2)
pc3 c2 (lift (S n) O x1) (lift (S n) O u)
                                  end of h3
                                  by (ty3_conv . . . . h1 . . h2 h3)
ty3 g c2 (TLRef n) (lift (S n) O u)
ty3 g c2 (TLRef n) (lift (S n) O u)
                      end of h1
                      (h2) 
                         by (pr0_gen_lref . . H4)
eq T t2 (TLRef n)
                      end of h2
                      by (eq_ind_r . . . h1 . h2)
                      we proved ty3 g c2 t2 (lift (S n) O u)
∀c2:C.∀H3:(wcpr0 c c2).∀t2:T.∀H4:(pr0 (TLRef n) t2).(ty3 g c2 t2 (lift (S n) O u))
             case ty3_bind : c:C u:T t0:T :ty3 g c u t0 b:B t2:T t3:T H2:ty3 g (CHead c (Bind b) u) t2 t3 ⇒
                the thesis becomes ∀c2:C.∀H4:(wcpr0 c c2).∀t4:T.∀H5:(pr0 (THead (Bind b) u t2) t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                (H1) by induction hypothesis we know ∀c2:C.(wcpr0 c c2)→∀t2:T.(pr0 u t2)→(ty3 g c2 t2 t0)
                (H3) by induction hypothesis we know ∀c2:C.(wcpr0 (CHead c (Bind b) u) c2)→∀t4:T.(pr0 t2 t4)→(ty3 g c2 t4 t3)
                    assume c2: C
                    suppose H4: wcpr0 c c2
                    assume t4: T
                    suppose H5: pr0 (THead (Bind b) u t2) t4
                      (H6) 
                         by cases on H5 we prove 
                            eq T (THead (Bind b) u t2) (THead (Bind b) u t2)
                              →(eq T t4 t4)→(ty3 g c2 t4 (THead (Bind b) u t3))
                            case pr0_refl t5:T ⇒
                               the thesis becomes ∀H6:(eq T t5 (THead (Bind b) u t2)).∀H7:(eq T t5 t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                                suppose H6: eq T t5 (THead (Bind b) u t2)
                                suppose H7: eq T t5 t4
                                  by (sym_eq . . . H6)
                                  we proved eq T (THead (Bind b) u t2) t5
                                  suppose H8: eq T (THead (Bind b) u t2) t4
                                     we proceed by induction on H8 to prove ty3 g c2 t4 (THead (Bind b) u t3)
                                        case refl_equal : ⇒
                                           the thesis becomes ty3 g c2 (THead (Bind b) u t2) (THead (Bind b) u t3)
                                              (h1) 
                                                 by (pr0_refl .)
                                                 we proved pr0 u u
                                                 by (H1 . H4 . previous)
ty3 g c2 u t0
                                              end of h1
                                              (h2) 
                                                 (h1) 
                                                    by (pr0_refl .)
                                                    we proved pr0 u u
                                                    by (wcpr0_comp . . H4 . . previous .)
wcpr0 (CHead c (Bind b) u) (CHead c2 (Bind b) u)
                                                 end of h1
                                                 (h2) by (pr0_refl .) we proved pr0 t2 t2
                                                 by (H3 . h1 . h2)
ty3 g (CHead c2 (Bind b) u) t2 t3
                                              end of h2
                                              by (ty3_bind . . . . h1 . . . h2)
ty3 g c2 (THead (Bind b) u t2) (THead (Bind b) u t3)
                                     we proved ty3 g c2 t4 (THead (Bind b) u t3)
(eq T (THead (Bind b) u t2) t4)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                  by (previous previous H7)
                                  we proved ty3 g c2 t4 (THead (Bind b) u t3)
∀H6:(eq T t5 (THead (Bind b) u t2)).∀H7:(eq T t5 t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                            case pr0_comp u1:T u2:T H6:pr0 u1 u2 t5:T t6:T H7:pr0 t5 t6 k:K ⇒
                               the thesis becomes 
                                     ∀H8:eq T (THead k u1 t5) (THead (Bind b) u t2)
                                       .∀H9:(eq T (THead k u2 t6) t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                                suppose H8: eq T (THead k u1 t5) (THead (Bind b) u t2)
                                suppose H9: eq T (THead k u2 t6) t4
                                  (H10) 
                                     by (f_equal . . . . . H8)
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead k u1 t5 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                          <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7

                                        eq
                                          T
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7 (THead k u1 t5)
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                            THead (Bind b) u t2
                                  end of H10
                                  (h1) 
                                     (H11) 
                                        by (f_equal . . . . . H8)
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead k u1 t5 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7

                                           eq
                                             T
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7 (THead k u1 t5)
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                               THead (Bind b) u t2
                                     end of H11
                                     (h1) 
                                        (H12) 
                                           by (f_equal . . . . . H8)
                                           we proved 
                                              eq
                                                K
                                                <λ:T.K> CASE THead k u1 t5 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                                <λ:T.K> CASE THead (Bind b) u t2 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0

                                              eq
                                                K
                                                λe:T.<λ:T.K> CASE e OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0 (THead k u1 t5)
                                                λe:T.<λ:T.K> CASE e OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                                  THead (Bind b) u t2
                                        end of H12
                                        consider H12
                                        we proved 
                                           eq
                                             K
                                             <λ:T.K> CASE THead k u1 t5 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                             <λ:T.K> CASE THead (Bind b) u t2 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                        that is equivalent to eq K k (Bind b)
                                        by (sym_eq . . . previous)
                                        we proved eq K (Bind b) k
                                        we proceed by induction on the previous result to prove 
                                           eq T u1 u
                                             →(eq T t5 t2
                                                  →(eq T (THead k u2 t6) t4
                                                       →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))))
                                           case refl_equal : ⇒
                                              the thesis becomes 
                                              eq T u1 u
                                                →(eq T t5 t2
                                                     →(eq T (THead (Bind b) u2 t6) t4
                                                          →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))))
                                                 suppose H13: eq T u1 u
                                                    by (sym_eq . . . H13)
                                                    we proved eq T u u1
                                                    we proceed by induction on the previous result to prove 
                                                       eq T t5 t2
                                                         →(eq T (THead (Bind b) u2 t6) t4
                                                              →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                                       case refl_equal : ⇒
                                                          the thesis becomes 
                                                          eq T t5 t2
                                                            →(eq T (THead (Bind b) u2 t6) t4
                                                                 →(pr0 u u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                                             suppose H14: eq T t5 t2
                                                                by (sym_eq . . . H14)
                                                                we proved eq T t2 t5
                                                                we proceed by induction on the previous result to prove 
                                                                   eq T (THead (Bind b) u2 t6) t4
                                                                     →(pr0 u u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                   case refl_equal : ⇒
                                                                      the thesis becomes 
                                                                      eq T (THead (Bind b) u2 t6) t4
                                                                        →(pr0 u u2)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                         suppose H15: eq T (THead (Bind b) u2 t6) t4
                                                                            we proceed by induction on H15 to prove (pr0 u u2)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                               case refl_equal : ⇒
                                                                                  the thesis becomes (pr0 u u2)→(pr0 t2 t6)→(ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3))
                                                                                      suppose H16: pr0 u u2
                                                                                      suppose H17: pr0 t2 t6
                                                                                        (h1) 
                                                                                           by (pr0_refl .)
                                                                                           we proved pr0 u u
                                                                                           by (wcpr0_comp . . H4 . . previous .)
wcpr0 (CHead c (Bind b) u) (CHead c2 (Bind b) u)
                                                                                        end of h1
                                                                                        (h2) by (pr0_refl .) we proved pr0 t2 t2
                                                                                        by (H3 . h1 . h2)
                                                                                        we proved ty3 g (CHead c2 (Bind b) u) t2 t3
                                                                                        by (ty3_correct . . . . previous)
                                                                                        we proved ex T λt:T.ty3 g (CHead c2 (Bind b) u) t3 t
                                                                                        we proceed by induction on the previous result to prove ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3)
                                                                                           case ex_intro : x:T H18:ty3 g (CHead c2 (Bind b) u) t3 x ⇒
                                                                                              the thesis becomes ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3)
                                                                                                 by (wcpr0_comp . . H4 . . H16 .)
                                                                                                 we proved wcpr0 (CHead c (Bind b) u) (CHead c2 (Bind b) u2)
                                                                                                 by (H3 . previous . H17)
                                                                                                 we proved ty3 g (CHead c2 (Bind b) u2) t6 t3
                                                                                                 by (ty3_correct . . . . previous)
                                                                                                 we proved ex T λt:T.ty3 g (CHead c2 (Bind b) u2) t3 t
                                                                                                 we proceed by induction on the previous result to prove ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3)
                                                                                                    case ex_intro : x0:T :ty3 g (CHead c2 (Bind b) u2) t3 x0 ⇒
                                                                                                       the thesis becomes ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3)
                                                                                                          (h1) 
                                                                                                             by (pr0_refl .)
                                                                                                             we proved pr0 u u
                                                                                                             by (H1 . H4 . previous)
                                                                                                             we proved ty3 g c2 u t0
                                                                                                             by (ty3_bind . . . . previous . . . H18)
ty3 g c2 (THead (Bind b) u t3) (THead (Bind b) u x)
                                                                                                          end of h1
                                                                                                          (h2) 
                                                                                                             (h1) by (H1 . H4 . H16) we proved ty3 g c2 u2 t0
                                                                                                             (h2) 
                                                                                                                by (wcpr0_comp . . H4 . . H16 .)
                                                                                                                we proved wcpr0 (CHead c (Bind b) u) (CHead c2 (Bind b) u2)
                                                                                                                by (H3 . previous . H17)
ty3 g (CHead c2 (Bind b) u2) t6 t3
                                                                                                             end of h2
                                                                                                             by (ty3_bind . . . . h1 . . . h2)
ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u2 t3)
                                                                                                          end of h2
                                                                                                          (h3) 
                                                                                                             by (pr2_free . . . H16)
                                                                                                             we proved pr2 c2 u u2
                                                                                                             by (pr2_head_1 . . . previous . .)
                                                                                                             we proved pr2 c2 (THead (Bind b) u t3) (THead (Bind b) u2 t3)
                                                                                                             by (pc3_pr2_x . . . previous)
pc3 c2 (THead (Bind b) u2 t3) (THead (Bind b) u t3)
                                                                                                          end of h3
                                                                                                          by (ty3_conv . . . . h1 . . h2 h3)
ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3)
ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3)
                                                                                        we proved ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3)
(pr0 u u2)→(pr0 t2 t6)→(ty3 g c2 (THead (Bind b) u2 t6) (THead (Bind b) u t3))
                                                                            we proved (pr0 u u2)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))

                                                                            eq T (THead (Bind b) u2 t6) t4
                                                                              →(pr0 u u2)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                we proved 
                                                                   eq T (THead (Bind b) u2 t6) t4
                                                                     →(pr0 u u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))

                                                                eq T t5 t2
                                                                  →(eq T (THead (Bind b) u2 t6) t4
                                                                       →(pr0 u u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                                    we proved 
                                                       eq T t5 t2
                                                         →(eq T (THead (Bind b) u2 t6) t4
                                                              →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))

                                                    eq T u1 u
                                                      →(eq T t5 t2
                                                           →(eq T (THead (Bind b) u2 t6) t4
                                                                →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))))

                                           eq T u1 u
                                             →(eq T t5 t2
                                                  →(eq T (THead k u2 t6) t4
                                                       →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))))
                                     end of h1
                                     (h2) 
                                        consider H11
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead k u1 t5 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
eq T u1 u
                                     end of h2
                                     by (h1 h2)

                                        eq T t5 t2
                                          →(eq T (THead k u2 t6) t4
                                               →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                  end of h1
                                  (h2) 
                                     consider H10
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead k u1 t5 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                          <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
eq T t5 t2
                                  end of h2
                                  by (h1 h2)
                                  we proved 
                                     eq T (THead k u2 t6) t4
                                       →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t4 (THead (Bind b) u t3)

                                  ∀H8:eq T (THead k u1 t5) (THead (Bind b) u t2)
                                    .∀H9:(eq T (THead k u2 t6) t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                            case pr0_beta u0:T v1:T v2:T H6:pr0 v1 v2 t5:T t6:T H7:pr0 t5 t6 ⇒
                               the thesis becomes 
                                     ∀H8:eq
                                                T
                                                THead (Flat Appl) v1 (THead (Bind Abst) u0 t5)
                                                THead (Bind b) u t2
                                       .∀H9:(eq T (THead (Bind Abbr) v2 t6) t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                                suppose H8: 
                                   eq
                                     T
                                     THead (Flat Appl) v1 (THead (Bind Abst) u0 t5)
                                     THead (Bind b) u t2
                                suppose H9: eq T (THead (Bind Abbr) v2 t6) t4
                                  (H10) 
                                     we proceed by induction on H8 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Bind b) u t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Flat Appl) v1 (THead (Bind Abst) u0 t5) OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Flat Appl) v1 (THead (Bind Abst) u0 t5) OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True

                                        <λ:T.Prop>
                                          CASE THead (Bind b) u t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                  end of H10
                                  consider H10
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Bind b) u t2 OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T (THead (Bind Abbr) v2 t6) t4
                                       →(pr0 v1 v2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                  we proved 
                                     eq T (THead (Bind Abbr) v2 t6) t4
                                       →(pr0 v1 v2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t4 (THead (Bind b) u t3)

                                  ∀H8:eq
                                             T
                                             THead (Flat Appl) v1 (THead (Bind Abst) u0 t5)
                                             THead (Bind b) u t2
                                    .∀H9:(eq T (THead (Bind Abbr) v2 t6) t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                            case pr0_upsilon b0:B H6:not (eq B b0 Abst) v1:T v2:T H7:pr0 v1 v2 u1:T u2:T H8:pr0 u1 u2 t5:T t6:T H9:pr0 t5 t6 ⇒
                               the thesis becomes 
                                     ∀H10:eq
                                                  T
                                                  THead (Flat Appl) v1 (THead (Bind b0) u1 t5)
                                                  THead (Bind b) u t2
                                       .∀H11:eq T (THead (Bind b0) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                         .ty3 g c2 t4 (THead (Bind b) u t3)
                                suppose H10: 
                                   eq
                                     T
                                     THead (Flat Appl) v1 (THead (Bind b0) u1 t5)
                                     THead (Bind b) u t2
                                suppose H11: eq T (THead (Bind b0) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                  (H12) 
                                     we proceed by induction on H10 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Bind b) u t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Flat Appl) v1 (THead (Bind b0) u1 t5) OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Flat Appl) v1 (THead (Bind b0) u1 t5) OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True

                                        <λ:T.Prop>
                                          CASE THead (Bind b) u t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                  end of H12
                                  consider H12
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Bind b) u t2 OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T (THead (Bind b0) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                       →(not (eq B b0 Abst)
                                            →(pr0 v1 v2)→(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                  we proved 
                                     eq T (THead (Bind b0) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                       →(not (eq B b0 Abst)
                                            →(pr0 v1 v2)→(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                  by (previous H11 H6 H7 H8 H9)
                                  we proved ty3 g c2 t4 (THead (Bind b) u t3)

                                  ∀H10:eq
                                               T
                                               THead (Flat Appl) v1 (THead (Bind b0) u1 t5)
                                               THead (Bind b) u t2
                                    .∀H11:eq T (THead (Bind b0) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                      .ty3 g c2 t4 (THead (Bind b) u t3)
                            case pr0_delta u1:T u2:T H6:pr0 u1 u2 t5:T t6:T H7:pr0 t5 t6 w:T H8:subst0 O u2 t6 w ⇒
                               the thesis becomes 
                                     ∀H9:eq T (THead (Bind Abbr) u1 t5) (THead (Bind b) u t2)
                                       .∀H10:(eq T (THead (Bind Abbr) u2 w) t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                                suppose H9: eq T (THead (Bind Abbr) u1 t5) (THead (Bind b) u t2)
                                suppose H10: eq T (THead (Bind Abbr) u2 w) t4
                                  (H11) 
                                     by (f_equal . . . . . H9)
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead (Bind Abbr) u1 t5 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                          <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7

                                        eq
                                          T
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                            THead (Bind Abbr) u1 t5
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                            THead (Bind b) u t2
                                  end of H11
                                  (h1) 
                                     (H12) 
                                        by (f_equal . . . . . H9)
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead (Bind Abbr) u1 t5 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7

                                           eq
                                             T
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                               THead (Bind Abbr) u1 t5
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                               THead (Bind b) u t2
                                     end of H12
                                     (h1) 
                                        (H13) 
                                           by (f_equal . . . . . H9)
                                           we proved 
                                              eq
                                                B
                                                <λ:T.B>
                                                  CASE THead (Bind Abbr) u1 t5 OF
                                                    TSort ⇒Abbr
                                                  | TLRef ⇒Abbr
                                                  | THead k  ⇒<λ:K.B> CASE k OF Bind b0⇒b0 | Flat ⇒Abbr
                                                <λ:T.B>
                                                  CASE THead (Bind b) u t2 OF
                                                    TSort ⇒Abbr
                                                  | TLRef ⇒Abbr
                                                  | THead k  ⇒<λ:K.B> CASE k OF Bind b0⇒b0 | Flat ⇒Abbr

                                              eq
                                                B
                                                λe:T
                                                    .<λ:T.B>
                                                      CASE e OF
                                                        TSort ⇒Abbr
                                                      | TLRef ⇒Abbr
                                                      | THead k  ⇒<λ:K.B> CASE k OF Bind b0⇒b0 | Flat ⇒Abbr
                                                  THead (Bind Abbr) u1 t5
                                                λe:T
                                                    .<λ:T.B>
                                                      CASE e OF
                                                        TSort ⇒Abbr
                                                      | TLRef ⇒Abbr
                                                      | THead k  ⇒<λ:K.B> CASE k OF Bind b0⇒b0 | Flat ⇒Abbr
                                                  THead (Bind b) u t2
                                        end of H13
                                        consider H13
                                        we proved 
                                           eq
                                             B
                                             <λ:T.B>
                                               CASE THead (Bind Abbr) u1 t5 OF
                                                 TSort ⇒Abbr
                                               | TLRef ⇒Abbr
                                               | THead k  ⇒<λ:K.B> CASE k OF Bind b0⇒b0 | Flat ⇒Abbr
                                             <λ:T.B>
                                               CASE THead (Bind b) u t2 OF
                                                 TSort ⇒Abbr
                                               | TLRef ⇒Abbr
                                               | THead k  ⇒<λ:K.B> CASE k OF Bind b0⇒b0 | Flat ⇒Abbr
                                        that is equivalent to eq B Abbr b
                                        we proceed by induction on the previous result to prove 
                                           eq T u1 u
                                             →(eq T t5 t2
                                                  →(eq T (THead (Bind Abbr) u2 w) t4
                                                       →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind b) u t3))))
                                           case refl_equal : ⇒
                                              the thesis becomes 
                                              eq T u1 u
                                                →(eq T t5 t2
                                                     →(eq T (THead (Bind Abbr) u2 w) t4
                                                          →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3))))
                                                 suppose H14: eq T u1 u
                                                    by (sym_eq . . . H14)
                                                    we proved eq T u u1
                                                    we proceed by induction on the previous result to prove 
                                                       eq T t5 t2
                                                         →(eq T (THead (Bind Abbr) u2 w) t4
                                                              →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3)))
                                                       case refl_equal : ⇒
                                                          the thesis becomes 
                                                          eq T t5 t2
                                                            →(eq T (THead (Bind Abbr) u2 w) t4
                                                                 →(pr0 u u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3)))
                                                             suppose H15: eq T t5 t2
                                                                by (sym_eq . . . H15)
                                                                we proved eq T t2 t5
                                                                we proceed by induction on the previous result to prove 
                                                                   eq T (THead (Bind Abbr) u2 w) t4
                                                                     →(pr0 u u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3))
                                                                   case refl_equal : ⇒
                                                                      the thesis becomes 
                                                                      eq T (THead (Bind Abbr) u2 w) t4
                                                                        →(pr0 u u2)→(pr0 t2 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3))
                                                                         suppose H16: eq T (THead (Bind Abbr) u2 w) t4
                                                                            we proceed by induction on H16 to prove (pr0 u u2)→(pr0 t2 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3))
                                                                               case refl_equal : ⇒
                                                                                  the thesis becomes 
                                                                                  pr0 u u2
                                                                                    →(pr0 t2 t6
                                                                                         →(subst0 O u2 t6 w)→(ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)))
                                                                                      suppose H17: pr0 u u2
                                                                                      suppose H18: pr0 t2 t6
                                                                                      suppose H19: subst0 O u2 t6 w
                                                                                        (H20) 
                                                                                           consider H13
                                                                                           we proved 
                                                                                              eq
                                                                                                B
                                                                                                <λ:T.B>
                                                                                                  CASE THead (Bind Abbr) u1 t5 OF
                                                                                                    TSort ⇒Abbr
                                                                                                  | TLRef ⇒Abbr
                                                                                                  | THead k  ⇒<λ:K.B> CASE k OF Bind b0⇒b0 | Flat ⇒Abbr
                                                                                                <λ:T.B>
                                                                                                  CASE THead (Bind b) u t2 OF
                                                                                                    TSort ⇒Abbr
                                                                                                  | TLRef ⇒Abbr
                                                                                                  | THead k  ⇒<λ:K.B> CASE k OF Bind b0⇒b0 | Flat ⇒Abbr
                                                                                           that is equivalent to eq B Abbr b
                                                                                           by (eq_ind_r . . . H3 . previous)
∀c3:C.(wcpr0 (CHead c (Bind Abbr) u) c3)→∀t7:T.(pr0 t2 t7)→(ty3 g c3 t7 t3)
                                                                                        end of H20
                                                                                        (h1) 
                                                                                           by (pr0_refl .)
                                                                                           we proved pr0 u u
                                                                                           by (wcpr0_comp . . H4 . . previous .)
wcpr0 (CHead c (Bind Abbr) u) (CHead c2 (Bind Abbr) u)
                                                                                        end of h1
                                                                                        (h2) by (pr0_refl .) we proved pr0 t2 t2
                                                                                        by (H20 . h1 . h2)
                                                                                        we proved ty3 g (CHead c2 (Bind Abbr) u) t2 t3
                                                                                        by (ty3_correct . . . . previous)
                                                                                        we proved ex T λt:T.ty3 g (CHead c2 (Bind Abbr) u) t3 t
                                                                                        we proceed by induction on the previous result to prove ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)
                                                                                           case ex_intro : x:T H22:ty3 g (CHead c2 (Bind Abbr) u) t3 x ⇒
                                                                                              the thesis becomes ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)
                                                                                                 by (wcpr0_comp . . H4 . . H17 .)
                                                                                                 we proved wcpr0 (CHead c (Bind Abbr) u) (CHead c2 (Bind Abbr) u2)
                                                                                                 by (H20 . previous . H18)
                                                                                                 we proved ty3 g (CHead c2 (Bind Abbr) u2) t6 t3
                                                                                                 by (ty3_correct . . . . previous)
                                                                                                 we proved ex T λt:T.ty3 g (CHead c2 (Bind Abbr) u2) t3 t
                                                                                                 we proceed by induction on the previous result to prove ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)
                                                                                                    case ex_intro : x0:T :ty3 g (CHead c2 (Bind Abbr) u2) t3 x0 ⇒
                                                                                                       the thesis becomes ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)
                                                                                                          (h1) 
                                                                                                             by (pr0_refl .)
                                                                                                             we proved pr0 u u
                                                                                                             by (H1 . H4 . previous)
                                                                                                             we proved ty3 g c2 u t0
                                                                                                             by (ty3_bind . . . . previous . . . H22)
ty3 g c2 (THead (Bind Abbr) u t3) (THead (Bind Abbr) u x)
                                                                                                          end of h1
                                                                                                          (h2) 
                                                                                                             (h1) by (H1 . H4 . H17) we proved ty3 g c2 u2 t0
                                                                                                             (h2) 
                                                                                                                (h1) 
                                                                                                                   by (wcpr0_comp . . H4 . . H17 .)
                                                                                                                   we proved wcpr0 (CHead c (Bind Abbr) u) (CHead c2 (Bind Abbr) u2)
                                                                                                                   by (H20 . previous . H18)
ty3 g (CHead c2 (Bind Abbr) u2) t6 t3
                                                                                                                end of h1
                                                                                                                (h2) 
                                                                                                                   by (getl_refl . . .)
getl O (CHead c2 (Bind Abbr) u2) (CHead c2 (Bind Abbr) u2)
                                                                                                                end of h2
                                                                                                                by (ty3_subst0 . . . . h1 . . . h2 . H19)
ty3 g (CHead c2 (Bind Abbr) u2) w t3
                                                                                                             end of h2
                                                                                                             by (ty3_bind . . . . h1 . . . h2)
ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u2 t3)
                                                                                                          end of h2
                                                                                                          (h3) 
                                                                                                             by (pr2_free . . . H17)
                                                                                                             we proved pr2 c2 u u2
                                                                                                             by (pr2_head_1 . . . previous . .)
                                                                                                             we proved pr2 c2 (THead (Bind Abbr) u t3) (THead (Bind Abbr) u2 t3)
                                                                                                             by (pc3_pr2_x . . . previous)
pc3 c2 (THead (Bind Abbr) u2 t3) (THead (Bind Abbr) u t3)
                                                                                                          end of h3
                                                                                                          by (ty3_conv . . . . h1 . . h2 h3)
ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)
ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)
                                                                                        we proved ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)

                                                                                        pr0 u u2
                                                                                          →(pr0 t2 t6
                                                                                               →(subst0 O u2 t6 w)→(ty3 g c2 (THead (Bind Abbr) u2 w) (THead (Bind Abbr) u t3)))
                                                                            we proved (pr0 u u2)→(pr0 t2 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3))

                                                                            eq T (THead (Bind Abbr) u2 w) t4
                                                                              →(pr0 u u2)→(pr0 t2 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3))
                                                                we proved 
                                                                   eq T (THead (Bind Abbr) u2 w) t4
                                                                     →(pr0 u u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3))

                                                                eq T t5 t2
                                                                  →(eq T (THead (Bind Abbr) u2 w) t4
                                                                       →(pr0 u u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3)))
                                                    we proved 
                                                       eq T t5 t2
                                                         →(eq T (THead (Bind Abbr) u2 w) t4
                                                              →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3)))

                                                    eq T u1 u
                                                      →(eq T t5 t2
                                                           →(eq T (THead (Bind Abbr) u2 w) t4
                                                                →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind Abbr) u t3))))

                                           eq T u1 u
                                             →(eq T t5 t2
                                                  →(eq T (THead (Bind Abbr) u2 w) t4
                                                       →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind b) u t3))))
                                     end of h1
                                     (h2) 
                                        consider H12
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead (Bind Abbr) u1 t5 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
eq T u1 u
                                     end of h2
                                     by (h1 h2)

                                        eq T t5 t2
                                          →(eq T (THead (Bind Abbr) u2 w) t4
                                               →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                  end of h1
                                  (h2) 
                                     consider H11
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead (Bind Abbr) u1 t5 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                          <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
eq T t5 t2
                                  end of h2
                                  by (h1 h2)
                                  we proved 
                                     eq T (THead (Bind Abbr) u2 w) t4
                                       →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                  by (previous H10 H6 H7 H8)
                                  we proved ty3 g c2 t4 (THead (Bind b) u t3)

                                  ∀H9:eq T (THead (Bind Abbr) u1 t5) (THead (Bind b) u t2)
                                    .∀H10:(eq T (THead (Bind Abbr) u2 w) t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                            case pr0_zeta b0:B H6:not (eq B b0 Abst) t5:T t6:T H7:pr0 t5 t6 u0:T ⇒
                               the thesis becomes 
                                     ∀H8:eq T (THead (Bind b0) u0 (lift (S O) O t5)) (THead (Bind b) u t2)
                                       .∀H9:(eq T t6 t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                                suppose H8: eq T (THead (Bind b0) u0 (lift (S O) O t5)) (THead (Bind b) u t2)
                                suppose H9: eq T t6 t4
                                  (H10) 
                                     by (f_equal . . . . . H8)
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T>
                                            CASE THead (Bind b0) u0 (lift (S O) O t5) OF
                                              TSort ⇒
                                                  FIXlref_map{
                                                      lref_map:(nat→nat)→nat→T→T
                                                      :=λf:nat→nat
                                                        .λd:nat
                                                          .λt7:T
                                                            .<λt8:T.T>
                                                              CASE t7 OF
                                                                TSort n⇒TSort n
                                                              | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                              | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                      }
                                                    λx:nat.plus x (S O)
                                                    O
                                                    t5
                                            | TLRef ⇒
                                                  FIXlref_map{
                                                      lref_map:(nat→nat)→nat→T→T
                                                      :=λf:nat→nat
                                                        .λd:nat
                                                          .λt7:T
                                                            .<λt8:T.T>
                                                              CASE t7 OF
                                                                TSort n⇒TSort n
                                                              | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                              | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                      }
                                                    λx:nat.plus x (S O)
                                                    O
                                                    t5
                                            | THead   t7⇒t7
                                          <λ:T.T>
                                            CASE THead (Bind b) u t2 OF
                                              TSort ⇒
                                                  FIXlref_map{
                                                      lref_map:(nat→nat)→nat→T→T
                                                      :=λf:nat→nat
                                                        .λd:nat
                                                          .λt7:T
                                                            .<λt8:T.T>
                                                              CASE t7 OF
                                                                TSort n⇒TSort n
                                                              | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                              | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                      }
                                                    λx:nat.plus x (S O)
                                                    O
                                                    t5
                                            | TLRef ⇒
                                                  FIXlref_map{
                                                      lref_map:(nat→nat)→nat→T→T
                                                      :=λf:nat→nat
                                                        .λd:nat
                                                          .λt7:T
                                                            .<λt8:T.T>
                                                              CASE t7 OF
                                                                TSort n⇒TSort n
                                                              | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                              | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                      }
                                                    λx:nat.plus x (S O)
                                                    O
                                                    t5
                                            | THead   t7⇒t7

                                        eq
                                          T
                                          λe:T
                                              .<λ:T.T>
                                                CASE e OF
                                                  TSort ⇒
                                                      FIXlref_map{
                                                          lref_map:(nat→nat)→nat→T→T
                                                          :=λf:nat→nat
                                                            .λd:nat
                                                              .λt7:T
                                                                .<λt8:T.T>
                                                                  CASE t7 OF
                                                                    TSort n⇒TSort n
                                                                  | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                                  | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                          }
                                                        λx:nat.plus x (S O)
                                                        O
                                                        t5
                                                | TLRef ⇒
                                                      FIXlref_map{
                                                          lref_map:(nat→nat)→nat→T→T
                                                          :=λf:nat→nat
                                                            .λd:nat
                                                              .λt7:T
                                                                .<λt8:T.T>
                                                                  CASE t7 OF
                                                                    TSort n⇒TSort n
                                                                  | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                                  | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                          }
                                                        λx:nat.plus x (S O)
                                                        O
                                                        t5
                                                | THead   t7⇒t7
                                            THead (Bind b0) u0 (lift (S O) O t5)
                                          λe:T
                                              .<λ:T.T>
                                                CASE e OF
                                                  TSort ⇒
                                                      FIXlref_map{
                                                          lref_map:(nat→nat)→nat→T→T
                                                          :=λf:nat→nat
                                                            .λd:nat
                                                              .λt7:T
                                                                .<λt8:T.T>
                                                                  CASE t7 OF
                                                                    TSort n⇒TSort n
                                                                  | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                                  | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                          }
                                                        λx:nat.plus x (S O)
                                                        O
                                                        t5
                                                | TLRef ⇒
                                                      FIXlref_map{
                                                          lref_map:(nat→nat)→nat→T→T
                                                          :=λf:nat→nat
                                                            .λd:nat
                                                              .λt7:T
                                                                .<λt8:T.T>
                                                                  CASE t7 OF
                                                                    TSort n⇒TSort n
                                                                  | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                                  | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                          }
                                                        λx:nat.plus x (S O)
                                                        O
                                                        t5
                                                | THead   t7⇒t7
                                            THead (Bind b) u t2
                                  end of H10
                                  (h1) 
                                     (H11) 
                                        by (f_equal . . . . . H8)
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T>
                                               CASE THead (Bind b0) u0 (lift (S O) O t5) OF
                                                 TSort ⇒u0
                                               | TLRef ⇒u0
                                               | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒u0 | TLRef ⇒u0 | THead  t7 ⇒t7

                                           eq
                                             T
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u0 | TLRef ⇒u0 | THead  t7 ⇒t7
                                               THead (Bind b0) u0 (lift (S O) O t5)
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u0 | TLRef ⇒u0 | THead  t7 ⇒t7
                                               THead (Bind b) u t2
                                     end of H11
                                     (h1) 
                                        (H12) 
                                           by (f_equal . . . . . H8)
                                           we proved 
                                              eq
                                                B
                                                <λ:T.B>
                                                  CASE THead (Bind b0) u0 (lift (S O) O t5) OF
                                                    TSort ⇒b0
                                                  | TLRef ⇒b0
                                                  | THead k  ⇒<λ:K.B> CASE k OF Bind b1⇒b1 | Flat ⇒b0
                                                <λ:T.B>
                                                  CASE THead (Bind b) u t2 OF
                                                    TSort ⇒b0
                                                  | TLRef ⇒b0
                                                  | THead k  ⇒<λ:K.B> CASE k OF Bind b1⇒b1 | Flat ⇒b0

                                              eq
                                                B
                                                λe:T
                                                    .<λ:T.B>
                                                      CASE e OF
                                                        TSort ⇒b0
                                                      | TLRef ⇒b0
                                                      | THead k  ⇒<λ:K.B> CASE k OF Bind b1⇒b1 | Flat ⇒b0
                                                  THead (Bind b0) u0 (lift (S O) O t5)
                                                λe:T
                                                    .<λ:T.B>
                                                      CASE e OF
                                                        TSort ⇒b0
                                                      | TLRef ⇒b0
                                                      | THead k  ⇒<λ:K.B> CASE k OF Bind b1⇒b1 | Flat ⇒b0
                                                  THead (Bind b) u t2
                                        end of H12
                                        consider H12
                                        we proved 
                                           eq
                                             B
                                             <λ:T.B>
                                               CASE THead (Bind b0) u0 (lift (S O) O t5) OF
                                                 TSort ⇒b0
                                               | TLRef ⇒b0
                                               | THead k  ⇒<λ:K.B> CASE k OF Bind b1⇒b1 | Flat ⇒b0
                                             <λ:T.B>
                                               CASE THead (Bind b) u t2 OF
                                                 TSort ⇒b0
                                               | TLRef ⇒b0
                                               | THead k  ⇒<λ:K.B> CASE k OF Bind b1⇒b1 | Flat ⇒b0
                                        that is equivalent to eq B b0 b
                                        by (sym_eq . . . previous)
                                        we proved eq B b b0
                                        we proceed by induction on the previous result to prove 
                                           eq T u0 u
                                             →(eq T (lift (S O) O t5) t2
                                                  →(eq T t6 t4
                                                       →(not (eq B b0 Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))))
                                           case refl_equal : ⇒
                                              the thesis becomes 
                                              eq T u0 u
                                                →(eq T (lift (S O) O t5) t2
                                                     →(eq T t6 t4
                                                          →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))))
                                                 suppose H13: eq T u0 u
                                                    by (sym_eq . . . H13)
                                                    we proved eq T u u0
                                                    we proceed by induction on the previous result to prove 
                                                       eq T (lift (S O) O t5) t2
                                                         →(eq T t6 t4
                                                              →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                                       case refl_equal : ⇒
                                                          the thesis becomes 
                                                          eq T (lift (S O) O t5) t2
                                                            →(eq T t6 t4
                                                                 →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                                             suppose H14: eq T (lift (S O) O t5) t2
                                                                we proceed by induction on H14 to prove 
                                                                   eq T t6 t4
                                                                     →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                   case refl_equal : ⇒
                                                                      the thesis becomes 
                                                                      eq T t6 t4
                                                                        →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                         suppose H15: eq T t6 t4
                                                                            by (sym_eq . . . H15)
                                                                            we proved eq T t4 t6
                                                                            we proceed by induction on the previous result to prove (not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                               case refl_equal : ⇒
                                                                                  the thesis becomes (not (eq B b Abst))→(pr0 t5 t4)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                                      suppose H16: not (eq B b Abst)
                                                                                      suppose H17: pr0 t5 t4
                                                                                        (H18) 
                                                                                           by (eq_ind_r . . . H3 . H14)
∀c3:C.(wcpr0 (CHead c (Bind b) u) c3)→∀t8:T.(pr0 (lift (S O) O t5) t8)→(ty3 g c3 t8 t3)
                                                                                        end of H18
                                                                                        (h1) 
                                                                                           by (pr0_refl .)
                                                                                           we proved pr0 u u
                                                                                           by (wcpr0_comp . . H4 . . previous .)
wcpr0 (CHead c (Bind b) u) (CHead c2 (Bind b) u)
                                                                                        end of h1
                                                                                        (h2) 
                                                                                           by (pr0_lift . . H17 . .)
pr0 (lift (S O) O t5) (lift (S O) O t4)
                                                                                        end of h2
                                                                                        by (H18 . h1 . h2)
                                                                                        we proved ty3 g (CHead c2 (Bind b) u) (lift (S O) O t4) t3
                                                                                        by (ty3_correct . . . . previous)
                                                                                        we proved ex T λt:T.ty3 g (CHead c2 (Bind b) u) t3 t
                                                                                        we proceed by induction on the previous result to prove ty3 g c2 t4 (THead (Bind b) u t3)
                                                                                           case ex_intro : x:T H20:ty3 g (CHead c2 (Bind b) u) t3 x ⇒
                                                                                              the thesis becomes ty3 g c2 t4 (THead (Bind b) u t3)
                                                                                                 (h1) 
                                                                                                    by (pr0_refl .)
                                                                                                    we proved pr0 u u
                                                                                                    by (wcpr0_comp . . H4 . . previous .)
wcpr0 (CHead c (Bind b) u) (CHead c2 (Bind b) u)
                                                                                                 end of h1
                                                                                                 (h2) 
                                                                                                    by (pr0_lift . . H17 . .)
pr0 (lift (S O) O t5) (lift (S O) O t4)
                                                                                                 end of h2
                                                                                                 by (H18 . h1 . h2)
                                                                                                 we proved ty3 g (CHead c2 (Bind b) u) (lift (S O) O t4) t3
                                                                                                  suppose H21: not (eq B Abbr Abst)
                                                                                                  suppose H22: ty3 g (CHead c2 (Bind Abbr) u) t3 x
                                                                                                  suppose H23: ty3 g (CHead c2 (Bind Abbr) u) (lift (S O) O t4) t3
                                                                                                    (H24) 
                                                                                                       (h1) 
                                                                                                          by (getl_refl . . .)
getl O (CHead c2 (Bind Abbr) u) (CHead c2 (Bind Abbr) u)
                                                                                                       end of h1
                                                                                                       (h2) 
                                                                                                          by (csubst1_refl . . .)
csubst1 O u (CHead c2 (Bind Abbr) u) (CHead c2 (Bind Abbr) u)
                                                                                                       end of h2
                                                                                                       (h3) 
                                                                                                          by (drop_refl .)
                                                                                                          we proved drop O O c2 c2
                                                                                                          that is equivalent to drop (r (Bind Abbr) O) O c2 c2
                                                                                                          by (drop_drop . . . . previous .)
drop (S O) O (CHead c2 (Bind Abbr) u) c2
                                                                                                       end of h3
                                                                                                       by (ty3_gen_cabbr . . . . H23 . . . h1 . h2 . h3)

                                                                                                          ex3_2
                                                                                                            T
                                                                                                            T
                                                                                                            λy1:T.λ:T.subst1 O u (lift (S O) O t4) (lift (S O) O y1)
                                                                                                            λ:T.λy2:T.subst1 O u t3 (lift (S O) O y2)
                                                                                                            λy1:T.λy2:T.ty3 g c2 y1 y2
                                                                                                    end of H24
                                                                                                    we proceed by induction on H24 to prove ty3 g c2 t4 (THead (Bind Abbr) u t3)
                                                                                                       case ex3_2_intro : x0:T x1:T H25:subst1 O u (lift (S O) O t4) (lift (S O) O x0) H26:subst1 O u t3 (lift (S O) O x1) H27:ty3 g c2 x0 x1 ⇒
                                                                                                          the thesis becomes ty3 g c2 t4 (THead (Bind Abbr) u t3)
                                                                                                             (H28) 
                                                                                                                (h1) by (le_n .) we proved le O O
                                                                                                                (h2) 
                                                                                                                   (h1) 
                                                                                                                      by (le_n .)
                                                                                                                      we proved le (plus (S O) O) (plus (S O) O)
lt O (plus (S O) O)
                                                                                                                   end of h1
                                                                                                                   (h2) 
                                                                                                                      by (plus_sym . .)
eq nat (plus O (S O)) (plus (S O) O)
                                                                                                                   end of h2
                                                                                                                   by (eq_ind_r . . . h1 . h2)
lt O (plus O (S O))
                                                                                                                end of h2
                                                                                                                by (subst1_gen_lift_eq . . . . . . h1 h2 H25)
                                                                                                                we proved eq T (lift (S O) O x0) (lift (S O) O t4)
                                                                                                                by (lift_inj . . . . previous)
                                                                                                                we proved eq T x0 t4
                                                                                                                we proceed by induction on the previous result to prove ty3 g c2 t4 x1
                                                                                                                   case refl_equal : ⇒
                                                                                                                      the thesis becomes the hypothesis H27
ty3 g c2 t4 x1
                                                                                                             end of H28
                                                                                                             (h1) 
                                                                                                                by (pr0_refl .)
                                                                                                                we proved pr0 u u
                                                                                                                by (H1 . H4 . previous)
                                                                                                                we proved ty3 g c2 u t0
                                                                                                                by (ty3_bind . . . . previous . . . H22)
ty3 g c2 (THead (Bind Abbr) u t3) (THead (Bind Abbr) u x)
                                                                                                             end of h1
                                                                                                             (h2) 
                                                                                                                (h1) 
                                                                                                                   (h1) by (pr0_refl .) we proved pr0 u u
                                                                                                                   (h2) by (pr0_refl .) we proved pr0 t3 t3
                                                                                                                   by (pr0_delta1 . . h1 . . h2 . H26)
                                                                                                                   we proved 
                                                                                                                      pr0
                                                                                                                        THead (Bind Abbr) u t3
                                                                                                                        THead (Bind Abbr) u (lift (S O) O x1)
                                                                                                                   by (pr2_free . . . previous)
                                                                                                                   we proved 
                                                                                                                      pr2
                                                                                                                        c2
                                                                                                                        THead (Bind Abbr) u t3
                                                                                                                        THead (Bind Abbr) u (lift (S O) O x1)
                                                                                                                   by (pr3_pr2 . . . previous)

                                                                                                                      pr3
                                                                                                                        c2
                                                                                                                        THead (Bind Abbr) u t3
                                                                                                                        THead (Bind Abbr) u (lift (S O) O x1)
                                                                                                                end of h1
                                                                                                                (h2) 
                                                                                                                   by (pr0_refl .)
                                                                                                                   we proved pr0 x1 x1
                                                                                                                   by (pr0_zeta . H21 . . previous .)
                                                                                                                   we proved pr0 (THead (Bind Abbr) u (lift (S O) O x1)) x1
                                                                                                                   by (pr2_free . . . previous)
                                                                                                                   we proved pr2 c2 (THead (Bind Abbr) u (lift (S O) O x1)) x1
                                                                                                                   by (pr3_pr2 . . . previous)
pr3 c2 (THead (Bind Abbr) u (lift (S O) O x1)) x1
                                                                                                                end of h2
                                                                                                                by (pr3_t . . . h1 . h2)
                                                                                                                we proved pr3 c2 (THead (Bind Abbr) u t3) x1
                                                                                                                by (pc3_pr3_x . . . previous)
pc3 c2 x1 (THead (Bind Abbr) u t3)
                                                                                                             end of h2
                                                                                                             by (ty3_conv . . . . h1 . . H28 h2)
ty3 g c2 t4 (THead (Bind Abbr) u t3)
                                                                                                    we proved ty3 g c2 t4 (THead (Bind Abbr) u t3)

                                                                                                    not (eq B Abbr Abst)
                                                                                                      →(ty3 g (CHead c2 (Bind Abbr) u) t3 x
                                                                                                           →(ty3 g (CHead c2 (Bind Abbr) u) (lift (S O) O t4) t3
                                                                                                                →ty3 g c2 t4 (THead (Bind Abbr) u t3)))
                                                                                                  suppose H21: not (eq B Abst Abst)
                                                                                                  suppose : ty3 g (CHead c2 (Bind Abst) u) t3 x
                                                                                                  suppose : ty3 g (CHead c2 (Bind Abst) u) (lift (S O) O t4) t3
                                                                                                    (H24) 
                                                                                                       by (refl_equal . .)
                                                                                                       we proved eq B Abst Abst
                                                                                                       by (H21 previous)
                                                                                                       we proved False
                                                                                                       by cases on the previous result we prove ty3 g c2 t4 (THead (Bind Abst) u t3)
ty3 g c2 t4 (THead (Bind Abst) u t3)
                                                                                                    end of H24
                                                                                                    consider H24
                                                                                                    we proved ty3 g c2 t4 (THead (Bind Abst) u t3)

                                                                                                    not (eq B Abst Abst)
                                                                                                      →(ty3 g (CHead c2 (Bind Abst) u) t3 x
                                                                                                           →(ty3 g (CHead c2 (Bind Abst) u) (lift (S O) O t4) t3
                                                                                                                →ty3 g c2 t4 (THead (Bind Abst) u t3)))
                                                                                                  suppose H21: not (eq B Void Abst)
                                                                                                  suppose H22: ty3 g (CHead c2 (Bind Void) u) t3 x
                                                                                                  suppose H23: ty3 g (CHead c2 (Bind Void) u) (lift (S O) O t4) t3
                                                                                                    (H24) 
                                                                                                       (h1) 
                                                                                                          by (getl_refl . . .)
getl O (CHead c2 (Bind Void) u) (CHead c2 (Bind Void) u)
                                                                                                       end of h1
                                                                                                       (h2) 
                                                                                                          by (drop_refl .)
                                                                                                          we proved drop O O c2 c2
                                                                                                          that is equivalent to drop (r (Bind Void) O) O c2 c2
                                                                                                          by (drop_drop . . . . previous .)
drop (S O) O (CHead c2 (Bind Void) u) c2
                                                                                                       end of h2
                                                                                                       by (ty3_gen_cvoid . . . . H23 . . . h1 . h2)

                                                                                                          ex3_2
                                                                                                            T
                                                                                                            T
                                                                                                            λy1:T.λ:T.eq T (lift (S O) O t4) (lift (S O) O y1)
                                                                                                            λ:T.λy2:T.eq T t3 (lift (S O) O y2)
                                                                                                            λy1:T.λy2:T.ty3 g c2 y1 y2
                                                                                                    end of H24
                                                                                                    we proceed by induction on H24 to prove ty3 g c2 t4 (THead (Bind Void) u t3)
                                                                                                       case ex3_2_intro : x0:T x1:T H25:eq T (lift (S O) O t4) (lift (S O) O x0) H26:eq T t3 (lift (S O) O x1) H27:ty3 g c2 x0 x1 ⇒
                                                                                                          the thesis becomes ty3 g c2 t4 (THead (Bind Void) u t3)
                                                                                                             (H28) 
                                                                                                                we proceed by induction on H26 to prove ty3 g (CHead c2 (Bind Void) u) (lift (S O) O x1) x
                                                                                                                   case refl_equal : ⇒
                                                                                                                      the thesis becomes the hypothesis H22
ty3 g (CHead c2 (Bind Void) u) (lift (S O) O x1) x
                                                                                                             end of H28
                                                                                                             (H29) 
                                                                                                                by (lift_inj . . . . H25)
                                                                                                                we proved eq T t4 x0
                                                                                                                by (eq_ind_r . . . H27 . previous)
ty3 g c2 t4 x1
                                                                                                             end of H29
                                                                                                             (h1) 
                                                                                                                by (pr0_refl .)
                                                                                                                we proved pr0 u u
                                                                                                                by (H1 . H4 . previous)
                                                                                                                we proved ty3 g c2 u t0
                                                                                                                by (ty3_bind . . . . previous . . . H28)

                                                                                                                   ty3
                                                                                                                     g
                                                                                                                     c2
                                                                                                                     THead (Bind Void) u (lift (S O) O x1)
                                                                                                                     THead (Bind Void) u x
                                                                                                             end of h1
                                                                                                             (h2) 
                                                                                                                by (pr0_refl .)
                                                                                                                we proved pr0 x1 x1
                                                                                                                by (pr0_zeta . H21 . . previous .)
                                                                                                                we proved pr0 (THead (Bind Void) u (lift (S O) O x1)) x1
                                                                                                                by (pr2_free . . . previous)
                                                                                                                we proved pr2 c2 (THead (Bind Void) u (lift (S O) O x1)) x1
                                                                                                                by (pc3_pr2_r . . . previous)
                                                                                                                we proved pc3 c2 (THead (Bind Void) u (lift (S O) O x1)) x1
                                                                                                                by (pc3_s . . . previous)
pc3 c2 x1 (THead (Bind Void) u (lift (S O) O x1))
                                                                                                             end of h2
                                                                                                             by (ty3_conv . . . . h1 . . H29 h2)
                                                                                                             we proved ty3 g c2 t4 (THead (Bind Void) u (lift (S O) O x1))
                                                                                                             by (eq_ind_r . . . previous . H26)
ty3 g c2 t4 (THead (Bind Void) u t3)
                                                                                                    we proved ty3 g c2 t4 (THead (Bind Void) u t3)

                                                                                                    not (eq B Void Abst)
                                                                                                      →(ty3 g (CHead c2 (Bind Void) u) t3 x
                                                                                                           →(ty3 g (CHead c2 (Bind Void) u) (lift (S O) O t4) t3
                                                                                                                →ty3 g c2 t4 (THead (Bind Void) u t3)))
                                                                                                 by (previous . H16 H20 previous)
ty3 g c2 t4 (THead (Bind b) u t3)
                                                                                        we proved ty3 g c2 t4 (THead (Bind b) u t3)
(not (eq B b Abst))→(pr0 t5 t4)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                            we proved (not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))

                                                                            eq T t6 t4
                                                                              →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                                                we proved 
                                                                   eq T t6 t4
                                                                     →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))

                                                                eq T (lift (S O) O t5) t2
                                                                  →(eq T t6 t4
                                                                       →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                                    we proved 
                                                       eq T (lift (S O) O t5) t2
                                                         →(eq T t6 t4
                                                              →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))

                                                    eq T u0 u
                                                      →(eq T (lift (S O) O t5) t2
                                                           →(eq T t6 t4
                                                                →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))))

                                           eq T u0 u
                                             →(eq T (lift (S O) O t5) t2
                                                  →(eq T t6 t4
                                                       →(not (eq B b0 Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))))
                                     end of h1
                                     (h2) 
                                        consider H11
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T>
                                               CASE THead (Bind b0) u0 (lift (S O) O t5) OF
                                                 TSort ⇒u0
                                               | TLRef ⇒u0
                                               | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Bind b) u t2 OF TSort ⇒u0 | TLRef ⇒u0 | THead  t7 ⇒t7
eq T u0 u
                                     end of h2
                                     by (h1 h2)

                                        eq T (lift (S O) O t5) t2
                                          →(eq T t6 t4
                                               →(not (eq B b0 Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3)))
                                  end of h1
                                  (h2) 
                                     consider H10
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T>
                                            CASE THead (Bind b0) u0 (lift (S O) O t5) OF
                                              TSort ⇒
                                                  FIXlref_map{
                                                      lref_map:(nat→nat)→nat→T→T
                                                      :=λf:nat→nat
                                                        .λd:nat
                                                          .λt7:T
                                                            .<λt8:T.T>
                                                              CASE t7 OF
                                                                TSort n⇒TSort n
                                                              | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                              | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                      }
                                                    λx:nat.plus x (S O)
                                                    O
                                                    t5
                                            | TLRef ⇒
                                                  FIXlref_map{
                                                      lref_map:(nat→nat)→nat→T→T
                                                      :=λf:nat→nat
                                                        .λd:nat
                                                          .λt7:T
                                                            .<λt8:T.T>
                                                              CASE t7 OF
                                                                TSort n⇒TSort n
                                                              | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                              | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                      }
                                                    λx:nat.plus x (S O)
                                                    O
                                                    t5
                                            | THead   t7⇒t7
                                          <λ:T.T>
                                            CASE THead (Bind b) u t2 OF
                                              TSort ⇒
                                                  FIXlref_map{
                                                      lref_map:(nat→nat)→nat→T→T
                                                      :=λf:nat→nat
                                                        .λd:nat
                                                          .λt7:T
                                                            .<λt8:T.T>
                                                              CASE t7 OF
                                                                TSort n⇒TSort n
                                                              | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                              | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                      }
                                                    λx:nat.plus x (S O)
                                                    O
                                                    t5
                                            | TLRef ⇒
                                                  FIXlref_map{
                                                      lref_map:(nat→nat)→nat→T→T
                                                      :=λf:nat→nat
                                                        .λd:nat
                                                          .λt7:T
                                                            .<λt8:T.T>
                                                              CASE t7 OF
                                                                TSort n⇒TSort n
                                                              | TLRef i⇒TLRef <λb1:bool.nat> CASE blt i d OF true⇒i | false⇒f i
                                                              | THead k u1 t8⇒THead k (lref_map f d u1) (lref_map f (s k d) t8)
                                                      }
                                                    λx:nat.plus x (S O)
                                                    O
                                                    t5
                                            | THead   t7⇒t7
eq T (lift (S O) O t5) t2
                                  end of h2
                                  by (h1 h2)
                                  we proved 
                                     eq T t6 t4
                                       →(not (eq B b0 Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t4 (THead (Bind b) u t3)

                                  ∀H8:eq T (THead (Bind b0) u0 (lift (S O) O t5)) (THead (Bind b) u t2)
                                    .∀H9:(eq T t6 t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                            case pr0_tau t5:T t6:T H6:pr0 t5 t6 u0:T ⇒
                               the thesis becomes 
                                     ∀H7:eq T (THead (Flat Cast) u0 t5) (THead (Bind b) u t2)
                                       .∀H8:(eq T t6 t4).(ty3 g c2 t4 (THead (Bind b) u t3))
                                suppose H7: eq T (THead (Flat Cast) u0 t5) (THead (Bind b) u t2)
                                suppose H8: eq T t6 t4
                                  (H9) 
                                     we proceed by induction on H7 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Bind b) u t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Flat Cast) u0 t5 OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Flat Cast) u0 t5 OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True

                                        <λ:T.Prop>
                                          CASE THead (Bind b) u t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                  end of H9
                                  consider H9
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Bind b) u t2 OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒False | Flat ⇒True
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove (eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                  we proved (eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Bind b) u t3))
                                  by (previous H8 H6)
                                  we proved ty3 g c2 t4 (THead (Bind b) u t3)

                                  ∀H7:eq T (THead (Flat Cast) u0 t5) (THead (Bind b) u t2)
                                    .∀H8:(eq T t6 t4).(ty3 g c2 t4 (THead (Bind b) u t3))

                            eq T (THead (Bind b) u t2) (THead (Bind b) u t2)
                              →(eq T t4 t4)→(ty3 g c2 t4 (THead (Bind b) u t3))
                      end of H6
                      (h1) 
                         by (refl_equal . .)
eq T (THead (Bind b) u t2) (THead (Bind b) u t2)
                      end of h1
                      (h2) 
                         by (refl_equal . .)
eq T t4 t4
                      end of h2
                      by (H6 h1 h2)
                      we proved ty3 g c2 t4 (THead (Bind b) u t3)
∀c2:C.∀H4:(wcpr0 c c2).∀t4:T.∀H5:(pr0 (THead (Bind b) u t2) t4).(ty3 g c2 t4 (THead (Bind b) u t3))
             case ty3_appl : c:C w:T u:T :ty3 g c w u v:T t0:T H2:ty3 g c v (THead (Bind Abst) u t0) ⇒
                the thesis becomes 
                ∀c2:C
                  .∀H4:wcpr0 c c2
                    .∀t2:T
                      .∀H5:pr0 (THead (Flat Appl) w v) t2
                        .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                (H1) by induction hypothesis we know ∀c2:C.(wcpr0 c c2)→∀t2:T.(pr0 w t2)→(ty3 g c2 t2 u)
                (H3) by induction hypothesis we know ∀c2:C.(wcpr0 c c2)→∀t2:T.(pr0 v t2)→(ty3 g c2 t2 (THead (Bind Abst) u t0))
                    assume c2: C
                    suppose H4: wcpr0 c c2
                    assume t2: T
                    suppose H5: pr0 (THead (Flat Appl) w v) t2
                      (H6) 
                         by cases on H5 we prove 
                            eq T (THead (Flat Appl) w v) (THead (Flat Appl) w v)
                              →(eq T t2 t2)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                            case pr0_refl t3:T ⇒
                               the thesis becomes 
                                     ∀H6:eq T t3 (THead (Flat Appl) w v)
                                       .∀H7:(eq T t3 t2).(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                suppose H6: eq T t3 (THead (Flat Appl) w v)
                                suppose H7: eq T t3 t2
                                  by (sym_eq . . . H6)
                                  we proved eq T (THead (Flat Appl) w v) t3
                                  suppose H8: eq T (THead (Flat Appl) w v) t2
                                     we proceed by induction on H8 to prove ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           ty3
                                             g
                                             c2
                                             THead (Flat Appl) w v
                                             THead (Flat Appl) w (THead (Bind Abst) u t0)
                                              (h1) 
                                                 by (pr0_refl .)
                                                 we proved pr0 w w
                                                 by (H1 . H4 . previous)
ty3 g c2 w u
                                              end of h1
                                              (h2) 
                                                 by (pr0_refl .)
                                                 we proved pr0 v v
                                                 by (H3 . H4 . previous)
ty3 g c2 v (THead (Bind Abst) u t0)
                                              end of h2
                                              by (ty3_appl . . . . h1 . . h2)

                                                 ty3
                                                   g
                                                   c2
                                                   THead (Flat Appl) w v
                                                   THead (Flat Appl) w (THead (Bind Abst) u t0)
                                     we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                                     eq T (THead (Flat Appl) w v) t2
                                       →ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                                  by (previous previous H7)
                                  we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                                  ∀H6:eq T t3 (THead (Flat Appl) w v)
                                    .∀H7:(eq T t3 t2).(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                            case pr0_comp u1:T u2:T H6:pr0 u1 u2 t3:T t4:T H7:pr0 t3 t4 k:K ⇒
                               the thesis becomes 
                                     ∀H8:eq T (THead k u1 t3) (THead (Flat Appl) w v)
                                       .∀H9:eq T (THead k u2 t4) t2
                                         .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                                suppose H8: eq T (THead k u1 t3) (THead (Flat Appl) w v)
                                suppose H9: eq T (THead k u2 t4) t2
                                  (H10) 
                                     by (f_equal . . . . . H8)
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead k u1 t3 OF TSort ⇒t3 | TLRef ⇒t3 | THead   t5⇒t5
                                          <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒t3 | TLRef ⇒t3 | THead   t5⇒t5

                                        eq
                                          T
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t3 | TLRef ⇒t3 | THead   t5⇒t5 (THead k u1 t3)
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t3 | TLRef ⇒t3 | THead   t5⇒t5
                                            THead (Flat Appl) w v
                                  end of H10
                                  (h1) 
                                     (H11) 
                                        by (f_equal . . . . . H8)
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead k u1 t3 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t5 ⇒t5
                                             <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒u1 | TLRef ⇒u1 | THead  t5 ⇒t5

                                           eq
                                             T
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u1 | TLRef ⇒u1 | THead  t5 ⇒t5 (THead k u1 t3)
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u1 | TLRef ⇒u1 | THead  t5 ⇒t5
                                               THead (Flat Appl) w v
                                     end of H11
                                     (h1) 
                                        (H12) 
                                           by (f_equal . . . . . H8)
                                           we proved 
                                              eq
                                                K
                                                <λ:T.K> CASE THead k u1 t3 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                                <λ:T.K>
                                                  CASE THead (Flat Appl) w v OF
                                                    TSort ⇒k
                                                  | TLRef ⇒k
                                                  | THead k0  ⇒k0

                                              eq
                                                K
                                                λe:T.<λ:T.K> CASE e OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0 (THead k u1 t3)
                                                λe:T.<λ:T.K> CASE e OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                                  THead (Flat Appl) w v
                                        end of H12
                                        consider H12
                                        we proved 
                                           eq
                                             K
                                             <λ:T.K> CASE THead k u1 t3 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                             <λ:T.K>
                                               CASE THead (Flat Appl) w v OF
                                                 TSort ⇒k
                                               | TLRef ⇒k
                                               | THead k0  ⇒k0
                                        that is equivalent to eq K k (Flat Appl)
                                        by (sym_eq . . . previous)
                                        we proved eq K (Flat Appl) k
                                        we proceed by induction on the previous result to prove 
                                           eq T u1 w
                                             →(eq T t3 v
                                                  →(eq T (THead k u2 t4) t2
                                                       →(pr0 u1 u2
                                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))
                                           case refl_equal : ⇒
                                              the thesis becomes 
                                              eq T u1 w
                                                →(eq T t3 v
                                                     →(eq T (THead (Flat Appl) u2 t4) t2
                                                          →(pr0 u1 u2
                                                               →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))
                                                 suppose H13: eq T u1 w
                                                    by (sym_eq . . . H13)
                                                    we proved eq T w u1
                                                    we proceed by induction on the previous result to prove 
                                                       eq T t3 v
                                                         →(eq T (THead (Flat Appl) u2 t4) t2
                                                              →(pr0 u1 u2
                                                                   →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                                       case refl_equal : ⇒
                                                          the thesis becomes 
                                                          eq T t3 v
                                                            →(eq T (THead (Flat Appl) u2 t4) t2
                                                                 →(pr0 w u2
                                                                      →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                                             suppose H14: eq T t3 v
                                                                by (sym_eq . . . H14)
                                                                we proved eq T v t3
                                                                we proceed by induction on the previous result to prove 
                                                                   eq T (THead (Flat Appl) u2 t4) t2
                                                                     →(pr0 w u2
                                                                          →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                                                   case refl_equal : ⇒
                                                                      the thesis becomes 
                                                                      eq T (THead (Flat Appl) u2 t4) t2
                                                                        →(pr0 w u2
                                                                             →(pr0 v t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                                                         suppose H15: eq T (THead (Flat Appl) u2 t4) t2
                                                                            we proceed by induction on H15 to prove 
                                                                               pr0 w u2
                                                                                 →(pr0 v t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                                                               case refl_equal : ⇒
                                                                                  the thesis becomes 
                                                                                  pr0 w u2
                                                                                    →(pr0 v t4
                                                                                         →(ty3
                                                                                              g
                                                                                              c2
                                                                                              THead (Flat Appl) u2 t4
                                                                                              THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                                                                      suppose H16: pr0 w u2
                                                                                      suppose H17: pr0 v t4
                                                                                        by (pr0_refl .)
                                                                                        we proved pr0 v v
                                                                                        by (H3 . H4 . previous)
                                                                                        we proved ty3 g c2 v (THead (Bind Abst) u t0)
                                                                                        by (ty3_correct . . . . previous)
                                                                                        we proved ex T λt:T.ty3 g c2 (THead (Bind Abst) u t0) t
                                                                                        we proceed by induction on the previous result to prove 
                                                                                           ty3
                                                                                             g
                                                                                             c2
                                                                                             THead (Flat Appl) u2 t4
                                                                                             THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                           case ex_intro : x:T H18:ty3 g c2 (THead (Bind Abst) u t0) x ⇒
                                                                                              the thesis becomes 
                                                                                              ty3
                                                                                                g
                                                                                                c2
                                                                                                THead (Flat Appl) u2 t4
                                                                                                THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                 by (ty3_gen_bind . . . . . . H18)
                                                                                                 we proved 
                                                                                                    ex3_2
                                                                                                      T
                                                                                                      T
                                                                                                      λt2:T.λ:T.pc3 c2 (THead (Bind Abst) u t2) x
                                                                                                      λ:T.λt:T.ty3 g c2 u t
                                                                                                      λt2:T.λ:T.ty3 g (CHead c2 (Bind Abst) u) t0 t2
                                                                                                 we proceed by induction on the previous result to prove 
                                                                                                    ty3
                                                                                                      g
                                                                                                      c2
                                                                                                      THead (Flat Appl) u2 t4
                                                                                                      THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                    case ex3_2_intro : x0:T x1:T :pc3 c2 (THead (Bind Abst) u x0) x H20:ty3 g c2 u x1 H21:ty3 g (CHead c2 (Bind Abst) u) t0 x0 ⇒
                                                                                                       the thesis becomes 
                                                                                                       ty3
                                                                                                         g
                                                                                                         c2
                                                                                                         THead (Flat Appl) u2 t4
                                                                                                         THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                          (h1) 
                                                                                                             (h1) 
                                                                                                                by (pr0_refl .)
                                                                                                                we proved pr0 w w
                                                                                                                by (H1 . H4 . previous)
ty3 g c2 w u
                                                                                                             end of h1
                                                                                                             (h2) 
                                                                                                                by (ty3_bind . . . . H20 . . . H21)
ty3 g c2 (THead (Bind Abst) u t0) (THead (Bind Abst) u x0)
                                                                                                             end of h2
                                                                                                             by (ty3_appl . . . . h1 . . h2)

                                                                                                                ty3
                                                                                                                  g
                                                                                                                  c2
                                                                                                                  THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                  THead (Flat Appl) w (THead (Bind Abst) u x0)
                                                                                                          end of h1
                                                                                                          (h2) 
                                                                                                             (h1) by (H1 . H4 . H16) we proved ty3 g c2 u2 u
                                                                                                             (h2) 
                                                                                                                by (H3 . H4 . H17)
ty3 g c2 t4 (THead (Bind Abst) u t0)
                                                                                                             end of h2
                                                                                                             by (ty3_appl . . . . h1 . . h2)

                                                                                                                ty3
                                                                                                                  g
                                                                                                                  c2
                                                                                                                  THead (Flat Appl) u2 t4
                                                                                                                  THead (Flat Appl) u2 (THead (Bind Abst) u t0)
                                                                                                          end of h2
                                                                                                          (h3) 
                                                                                                             by (pr2_free . . . H16)
                                                                                                             we proved pr2 c2 w u2
                                                                                                             by (pr2_head_1 . . . previous . .)
                                                                                                             we proved 
                                                                                                                pr2
                                                                                                                  c2
                                                                                                                  THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                  THead (Flat Appl) u2 (THead (Bind Abst) u t0)
                                                                                                             by (pc3_pr2_x . . . previous)

                                                                                                                pc3
                                                                                                                  c2
                                                                                                                  THead (Flat Appl) u2 (THead (Bind Abst) u t0)
                                                                                                                  THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                          end of h3
                                                                                                          by (ty3_conv . . . . h1 . . h2 h3)

                                                                                                             ty3
                                                                                                               g
                                                                                                               c2
                                                                                                               THead (Flat Appl) u2 t4
                                                                                                               THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                                    ty3
                                                                                                      g
                                                                                                      c2
                                                                                                      THead (Flat Appl) u2 t4
                                                                                                      THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                        we proved 
                                                                                           ty3
                                                                                             g
                                                                                             c2
                                                                                             THead (Flat Appl) u2 t4
                                                                                             THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                        pr0 w u2
                                                                                          →(pr0 v t4
                                                                                               →(ty3
                                                                                                    g
                                                                                                    c2
                                                                                                    THead (Flat Appl) u2 t4
                                                                                                    THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                                                            we proved 
                                                                               pr0 w u2
                                                                                 →(pr0 v t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))

                                                                            eq T (THead (Flat Appl) u2 t4) t2
                                                                              →(pr0 w u2
                                                                                   →(pr0 v t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                                                we proved 
                                                                   eq T (THead (Flat Appl) u2 t4) t2
                                                                     →(pr0 w u2
                                                                          →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))

                                                                eq T t3 v
                                                                  →(eq T (THead (Flat Appl) u2 t4) t2
                                                                       →(pr0 w u2
                                                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                                    we proved 
                                                       eq T t3 v
                                                         →(eq T (THead (Flat Appl) u2 t4) t2
                                                              →(pr0 u1 u2
                                                                   →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))

                                                    eq T u1 w
                                                      →(eq T t3 v
                                                           →(eq T (THead (Flat Appl) u2 t4) t2
                                                                →(pr0 u1 u2
                                                                     →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))

                                           eq T u1 w
                                             →(eq T t3 v
                                                  →(eq T (THead k u2 t4) t2
                                                       →(pr0 u1 u2
                                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))
                                     end of h1
                                     (h2) 
                                        consider H11
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead k u1 t3 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t5 ⇒t5
                                             <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒u1 | TLRef ⇒u1 | THead  t5 ⇒t5
eq T u1 w
                                     end of h2
                                     by (h1 h2)

                                        eq T t3 v
                                          →(eq T (THead k u2 t4) t2
                                               →(pr0 u1 u2
                                                    →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                  end of h1
                                  (h2) 
                                     consider H10
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead k u1 t3 OF TSort ⇒t3 | TLRef ⇒t3 | THead   t5⇒t5
                                          <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒t3 | TLRef ⇒t3 | THead   t5⇒t5
eq T t3 v
                                  end of h2
                                  by (h1 h2)
                                  we proved 
                                     eq T (THead k u2 t4) t2
                                       →(pr0 u1 u2
                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                                  ∀H8:eq T (THead k u1 t3) (THead (Flat Appl) w v)
                                    .∀H9:eq T (THead k u2 t4) t2
                                      .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                            case pr0_beta u0:T v1:T v2:T H6:pr0 v1 v2 t3:T t4:T H7:pr0 t3 t4 ⇒
                               the thesis becomes 
                                     ∀H8:eq
                                                T
                                                THead (Flat Appl) v1 (THead (Bind Abst) u0 t3)
                                                THead (Flat Appl) w v
                                       .∀H9:eq T (THead (Bind Abbr) v2 t4) t2
                                         .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                                suppose H8: 
                                   eq
                                     T
                                     THead (Flat Appl) v1 (THead (Bind Abst) u0 t3)
                                     THead (Flat Appl) w v
                                suppose H9: eq T (THead (Bind Abbr) v2 t4) t2
                                  (H10) 
                                     by (f_equal . . . . . H8)
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T>
                                            CASE THead (Flat Appl) v1 (THead (Bind Abst) u0 t3) OF
                                              TSort ⇒THead (Bind Abst) u0 t3
                                            | TLRef ⇒THead (Bind Abst) u0 t3
                                            | THead   t5⇒t5
                                          <λ:T.T>
                                            CASE THead (Flat Appl) w v OF
                                              TSort ⇒THead (Bind Abst) u0 t3
                                            | TLRef ⇒THead (Bind Abst) u0 t3
                                            | THead   t5⇒t5

                                        eq
                                          T
                                          λe:T
                                              .<λ:T.T>
                                                CASE e OF
                                                  TSort ⇒THead (Bind Abst) u0 t3
                                                | TLRef ⇒THead (Bind Abst) u0 t3
                                                | THead   t5⇒t5
                                            THead (Flat Appl) v1 (THead (Bind Abst) u0 t3)
                                          λe:T
                                              .<λ:T.T>
                                                CASE e OF
                                                  TSort ⇒THead (Bind Abst) u0 t3
                                                | TLRef ⇒THead (Bind Abst) u0 t3
                                                | THead   t5⇒t5
                                            THead (Flat Appl) w v
                                  end of H10
                                  (h1) 
                                     (H11) 
                                        by (f_equal . . . . . H8)
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T>
                                               CASE THead (Flat Appl) v1 (THead (Bind Abst) u0 t3) OF
                                                 TSort ⇒v1
                                               | TLRef ⇒v1
                                               | THead  t5 ⇒t5
                                             <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒v1 | TLRef ⇒v1 | THead  t5 ⇒t5

                                           eq
                                             T
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒v1 | TLRef ⇒v1 | THead  t5 ⇒t5
                                               THead (Flat Appl) v1 (THead (Bind Abst) u0 t3)
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒v1 | TLRef ⇒v1 | THead  t5 ⇒t5
                                               THead (Flat Appl) w v
                                     end of H11
                                     consider H11
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T>
                                            CASE THead (Flat Appl) v1 (THead (Bind Abst) u0 t3) OF
                                              TSort ⇒v1
                                            | TLRef ⇒v1
                                            | THead  t5 ⇒t5
                                          <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒v1 | TLRef ⇒v1 | THead  t5 ⇒t5
                                     that is equivalent to eq T v1 w
                                     by (sym_eq . . . previous)
                                     we proved eq T w v1
                                     we proceed by induction on the previous result to prove 
                                        eq T (THead (Bind Abst) u0 t3) v
                                          →(eq T (THead (Bind Abbr) v2 t4) t2
                                               →(pr0 v1 v2
                                                    →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           eq T (THead (Bind Abst) u0 t3) v
                                             →(eq T (THead (Bind Abbr) v2 t4) t2
                                                  →(pr0 w v2
                                                       →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                              suppose H12: eq T (THead (Bind Abst) u0 t3) v
                                                 we proceed by induction on H12 to prove 
                                                    eq T (THead (Bind Abbr) v2 t4) t2
                                                      →(pr0 w v2
                                                           →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                                    case refl_equal : ⇒
                                                       the thesis becomes 
                                                       eq T (THead (Bind Abbr) v2 t4) t2
                                                         →(pr0 w v2
                                                              →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                                          suppose H13: eq T (THead (Bind Abbr) v2 t4) t2
                                                             we proceed by induction on H13 to prove 
                                                                pr0 w v2
                                                                  →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                                                case refl_equal : ⇒
                                                                   the thesis becomes 
                                                                   pr0 w v2
                                                                     →(pr0 t3 t4
                                                                          →(ty3
                                                                               g
                                                                               c2
                                                                               THead (Bind Abbr) v2 t4
                                                                               THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                                                       suppose H14: pr0 w v2
                                                                       suppose H15: pr0 t3 t4
                                                                         (H16) 
                                                                            by (eq_ind_r . . . H3 . H12)

                                                                               ∀c3:C
                                                                                 .wcpr0 c c3
                                                                                   →∀t6:T.(pr0 (THead (Bind Abst) u0 t3) t6)→(ty3 g c3 t6 (THead (Bind Abst) u t0))
                                                                         end of H16
                                                                         by (pr0_refl .)
                                                                         we proved pr0 (THead (Bind Abst) u0 t3) (THead (Bind Abst) u0 t3)
                                                                         by (H16 . H4 . previous)
                                                                         we proved ty3 g c2 (THead (Bind Abst) u0 t3) (THead (Bind Abst) u t0)
                                                                         by (ty3_correct . . . . previous)
                                                                         we proved ex T λt:T.ty3 g c2 (THead (Bind Abst) u t0) t
                                                                         we proceed by induction on the previous result to prove 
                                                                            ty3
                                                                              g
                                                                              c2
                                                                              THead (Bind Abbr) v2 t4
                                                                              THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                            case ex_intro : x:T H18:ty3 g c2 (THead (Bind Abst) u t0) x ⇒
                                                                               the thesis becomes 
                                                                               ty3
                                                                                 g
                                                                                 c2
                                                                                 THead (Bind Abbr) v2 t4
                                                                                 THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                  by (ty3_gen_bind . . . . . . H18)
                                                                                  we proved 
                                                                                     ex3_2
                                                                                       T
                                                                                       T
                                                                                       λt2:T.λ:T.pc3 c2 (THead (Bind Abst) u t2) x
                                                                                       λ:T.λt:T.ty3 g c2 u t
                                                                                       λt2:T.λ:T.ty3 g (CHead c2 (Bind Abst) u) t0 t2
                                                                                  we proceed by induction on the previous result to prove 
                                                                                     ty3
                                                                                       g
                                                                                       c2
                                                                                       THead (Bind Abbr) v2 t4
                                                                                       THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                     case ex3_2_intro : x0:T x1:T :pc3 c2 (THead (Bind Abst) u x0) x H20:ty3 g c2 u x1 H21:ty3 g (CHead c2 (Bind Abst) u) t0 x0 ⇒
                                                                                        the thesis becomes 
                                                                                        ty3
                                                                                          g
                                                                                          c2
                                                                                          THead (Bind Abbr) v2 t4
                                                                                          THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                           by (pr0_refl .)
                                                                                           we proved pr0 u0 u0
                                                                                           by (pr0_comp . . previous . . H15 .)
                                                                                           we proved pr0 (THead (Bind Abst) u0 t3) (THead (Bind Abst) u0 t4)
                                                                                           by (H16 . H4 . previous)
                                                                                           we proved ty3 g c2 (THead (Bind Abst) u0 t4) (THead (Bind Abst) u t0)
                                                                                           by (ty3_gen_bind . . . . . . previous)
                                                                                           we proved 
                                                                                              ex3_2
                                                                                                T
                                                                                                T
                                                                                                λt2:T.λ:T.pc3 c2 (THead (Bind Abst) u0 t2) (THead (Bind Abst) u t0)
                                                                                                λ:T.λt:T.ty3 g c2 u0 t
                                                                                                λt2:T.λ:T.ty3 g (CHead c2 (Bind Abst) u0) t4 t2
                                                                                           we proceed by induction on the previous result to prove 
                                                                                              ty3
                                                                                                g
                                                                                                c2
                                                                                                THead (Bind Abbr) v2 t4
                                                                                                THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                              case ex3_2_intro : x2:T x3:T H22:pc3 c2 (THead (Bind Abst) u0 x2) (THead (Bind Abst) u t0) H23:ty3 g c2 u0 x3 H24:ty3 g (CHead c2 (Bind Abst) u0) t4 x2 ⇒
                                                                                                 the thesis becomes 
                                                                                                 ty3
                                                                                                   g
                                                                                                   c2
                                                                                                   THead (Bind Abbr) v2 t4
                                                                                                   THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                    by (pc3_gen_abst . . . . . H22)
                                                                                                    we proved land (pc3 c2 u0 u) ∀b:B.∀u:T.(pc3 (CHead c2 (Bind b) u) x2 t0)
                                                                                                    we proceed by induction on the previous result to prove 
                                                                                                       ty3
                                                                                                         g
                                                                                                         c2
                                                                                                         THead (Bind Abbr) v2 t4
                                                                                                         THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                       case conj : H25:pc3 c2 u0 u H26:∀b:B.∀u1:T.(pc3 (CHead c2 (Bind b) u1) x2 t0) ⇒
                                                                                                          the thesis becomes 
                                                                                                          ty3
                                                                                                            g
                                                                                                            c2
                                                                                                            THead (Bind Abbr) v2 t4
                                                                                                            THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                             (h1) 
                                                                                                                (h1) 
                                                                                                                   by (pr0_refl .)
                                                                                                                   we proved pr0 w w
                                                                                                                   by (H1 . H4 . previous)
ty3 g c2 w u
                                                                                                                end of h1
                                                                                                                (h2) 
                                                                                                                   by (ty3_bind . . . . H20 . . . H21)
ty3 g c2 (THead (Bind Abst) u t0) (THead (Bind Abst) u x0)
                                                                                                                end of h2
                                                                                                                by (ty3_appl . . . . h1 . . h2)

                                                                                                                   ty3
                                                                                                                     g
                                                                                                                     c2
                                                                                                                     THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                     THead (Flat Appl) w (THead (Bind Abst) u x0)
                                                                                                             end of h1
                                                                                                             (h2) 
                                                                                                                (h1) by (H1 . H4 . H14) we proved ty3 g c2 v2 u
                                                                                                                (h2) 
                                                                                                                   (h1) by (H1 . H4 . H14) we proved ty3 g c2 v2 u
                                                                                                                   (h2) by (pc3_s . . . H25) we proved pc3 c2 u u0
                                                                                                                   by (ty3_conv . . . . H23 . . h1 h2)
                                                                                                                   we proved ty3 g c2 v2 u0
                                                                                                                   by (csubt_ty3_ld . . . . previous . . H24)
ty3 g (CHead c2 (Bind Abbr) v2) t4 x2
                                                                                                                end of h2
                                                                                                                by (ty3_bind . . . . h1 . . . h2)
ty3 g c2 (THead (Bind Abbr) v2 t4) (THead (Bind Abbr) v2 x2)
                                                                                                             end of h2
                                                                                                             (h3) 
                                                                                                                (h1) 
                                                                                                                   by (H26 . .)
                                                                                                                   we proved pc3 (CHead c2 (Bind Abbr) v2) x2 t0
                                                                                                                   by (pc3_head_2 . . . . . previous)
pc3 c2 (THead (Bind Abbr) v2 x2) (THead (Bind Abbr) v2 t0)
                                                                                                                end of h1
                                                                                                                (h2) 
                                                                                                                   by (pr0_refl .)
                                                                                                                   we proved pr0 t0 t0
                                                                                                                   by (pr0_beta . . . H14 . . previous)
                                                                                                                   we proved 
                                                                                                                      pr0
                                                                                                                        THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                        THead (Bind Abbr) v2 t0
                                                                                                                   by (pr2_free . . . previous)
                                                                                                                   we proved 
                                                                                                                      pr2
                                                                                                                        c2
                                                                                                                        THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                        THead (Bind Abbr) v2 t0
                                                                                                                   by (pc3_pr2_x . . . previous)

                                                                                                                      pc3
                                                                                                                        c2
                                                                                                                        THead (Bind Abbr) v2 t0
                                                                                                                        THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                end of h2
                                                                                                                by (pc3_t . . . h1 . h2)

                                                                                                                   pc3
                                                                                                                     c2
                                                                                                                     THead (Bind Abbr) v2 x2
                                                                                                                     THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                             end of h3
                                                                                                             by (ty3_conv . . . . h1 . . h2 h3)

                                                                                                                ty3
                                                                                                                  g
                                                                                                                  c2
                                                                                                                  THead (Bind Abbr) v2 t4
                                                                                                                  THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                                       ty3
                                                                                                         g
                                                                                                         c2
                                                                                                         THead (Bind Abbr) v2 t4
                                                                                                         THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                              ty3
                                                                                                g
                                                                                                c2
                                                                                                THead (Bind Abbr) v2 t4
                                                                                                THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                     ty3
                                                                                       g
                                                                                       c2
                                                                                       THead (Bind Abbr) v2 t4
                                                                                       THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                         we proved 
                                                                            ty3
                                                                              g
                                                                              c2
                                                                              THead (Bind Abbr) v2 t4
                                                                              THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                         pr0 w v2
                                                                           →(pr0 t3 t4
                                                                                →(ty3
                                                                                     g
                                                                                     c2
                                                                                     THead (Bind Abbr) v2 t4
                                                                                     THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                                             we proved 
                                                                pr0 w v2
                                                                  →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))

                                                             eq T (THead (Bind Abbr) v2 t4) t2
                                                               →(pr0 w v2
                                                                    →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                                 we proved 
                                                    eq T (THead (Bind Abbr) v2 t4) t2
                                                      →(pr0 w v2
                                                           →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))

                                                 eq T (THead (Bind Abst) u0 t3) v
                                                   →(eq T (THead (Bind Abbr) v2 t4) t2
                                                        →(pr0 w v2
                                                             →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))

                                        eq T (THead (Bind Abst) u0 t3) v
                                          →(eq T (THead (Bind Abbr) v2 t4) t2
                                               →(pr0 v1 v2
                                                    →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                  end of h1
                                  (h2) 
                                     consider H10
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T>
                                            CASE THead (Flat Appl) v1 (THead (Bind Abst) u0 t3) OF
                                              TSort ⇒THead (Bind Abst) u0 t3
                                            | TLRef ⇒THead (Bind Abst) u0 t3
                                            | THead   t5⇒t5
                                          <λ:T.T>
                                            CASE THead (Flat Appl) w v OF
                                              TSort ⇒THead (Bind Abst) u0 t3
                                            | TLRef ⇒THead (Bind Abst) u0 t3
                                            | THead   t5⇒t5
eq T (THead (Bind Abst) u0 t3) v
                                  end of h2
                                  by (h1 h2)
                                  we proved 
                                     eq T (THead (Bind Abbr) v2 t4) t2
                                       →(pr0 v1 v2
                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                                  ∀H8:eq
                                             T
                                             THead (Flat Appl) v1 (THead (Bind Abst) u0 t3)
                                             THead (Flat Appl) w v
                                    .∀H9:eq T (THead (Bind Abbr) v2 t4) t2
                                      .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                            case pr0_upsilon b:B H6:not (eq B b Abst) v1:T v2:T H7:pr0 v1 v2 u1:T u2:T H8:pr0 u1 u2 t3:T t4:T H9:pr0 t3 t4 ⇒
                               the thesis becomes 
                                     ∀H10:eq
                                                  T
                                                  THead (Flat Appl) v1 (THead (Bind b) u1 t3)
                                                  THead (Flat Appl) w v
                                       .∀H11:eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                         .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                                suppose H10: 
                                   eq
                                     T
                                     THead (Flat Appl) v1 (THead (Bind b) u1 t3)
                                     THead (Flat Appl) w v
                                suppose H11: eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                  (H12) 
                                     by (f_equal . . . . . H10)
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T>
                                            CASE THead (Flat Appl) v1 (THead (Bind b) u1 t3) OF
                                              TSort ⇒THead (Bind b) u1 t3
                                            | TLRef ⇒THead (Bind b) u1 t3
                                            | THead   t5⇒t5
                                          <λ:T.T>
                                            CASE THead (Flat Appl) w v OF
                                              TSort ⇒THead (Bind b) u1 t3
                                            | TLRef ⇒THead (Bind b) u1 t3
                                            | THead   t5⇒t5

                                        eq
                                          T
                                          λe:T
                                              .<λ:T.T>
                                                CASE e OF
                                                  TSort ⇒THead (Bind b) u1 t3
                                                | TLRef ⇒THead (Bind b) u1 t3
                                                | THead   t5⇒t5
                                            THead (Flat Appl) v1 (THead (Bind b) u1 t3)
                                          λe:T
                                              .<λ:T.T>
                                                CASE e OF
                                                  TSort ⇒THead (Bind b) u1 t3
                                                | TLRef ⇒THead (Bind b) u1 t3
                                                | THead   t5⇒t5
                                            THead (Flat Appl) w v
                                  end of H12
                                  (h1) 
                                     (H13) 
                                        by (f_equal . . . . . H10)
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T>
                                               CASE THead (Flat Appl) v1 (THead (Bind b) u1 t3) OF
                                                 TSort ⇒v1
                                               | TLRef ⇒v1
                                               | THead  t5 ⇒t5
                                             <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒v1 | TLRef ⇒v1 | THead  t5 ⇒t5

                                           eq
                                             T
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒v1 | TLRef ⇒v1 | THead  t5 ⇒t5
                                               THead (Flat Appl) v1 (THead (Bind b) u1 t3)
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒v1 | TLRef ⇒v1 | THead  t5 ⇒t5
                                               THead (Flat Appl) w v
                                     end of H13
                                     consider H13
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T>
                                            CASE THead (Flat Appl) v1 (THead (Bind b) u1 t3) OF
                                              TSort ⇒v1
                                            | TLRef ⇒v1
                                            | THead  t5 ⇒t5
                                          <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒v1 | TLRef ⇒v1 | THead  t5 ⇒t5
                                     that is equivalent to eq T v1 w
                                     by (sym_eq . . . previous)
                                     we proved eq T w v1
                                     we proceed by induction on the previous result to prove 
                                        eq T (THead (Bind b) u1 t3) v
                                          →(eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                               →(not (eq B b Abst)
                                                    →(pr0 v1 v2
                                                         →(pr0 u1 u2
                                                              →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))))
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           eq T (THead (Bind b) u1 t3) v
                                             →(eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                                  →(not (eq B b Abst)
                                                       →(pr0 w v2
                                                            →(pr0 u1 u2
                                                                 →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))))
                                              suppose H14: eq T (THead (Bind b) u1 t3) v
                                                 we proceed by induction on H14 to prove 
                                                    eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                                      →(not (eq B b Abst)
                                                           →(pr0 w v2
                                                                →(pr0 u1 u2
                                                                     →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))
                                                    case refl_equal : ⇒
                                                       the thesis becomes 
                                                       eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                                         →(not (eq B b Abst)
                                                              →(pr0 w v2
                                                                   →(pr0 u1 u2
                                                                        →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))
                                                          suppose H15: eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                                             we proceed by induction on H15 to prove 
                                                                not (eq B b Abst)
                                                                  →(pr0 w v2
                                                                       →(pr0 u1 u2
                                                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                                                case refl_equal : ⇒
                                                                   the thesis becomes 
                                                                   not (eq B b Abst)
                                                                     →(pr0 w v2
                                                                          →(pr0 u1 u2
                                                                               →(pr0 t3 t4
                                                                                    →(ty3
                                                                                         g
                                                                                         c2
                                                                                         THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                         THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                                                       suppose H16: not (eq B b Abst)
                                                                       suppose H17: pr0 w v2
                                                                       suppose H18: pr0 u1 u2
                                                                       suppose H19: pr0 t3 t4
                                                                         (H20) 
                                                                            by (eq_ind_r . . . H3 . H14)

                                                                               ∀c3:C
                                                                                 .wcpr0 c c3
                                                                                   →∀t6:T.(pr0 (THead (Bind b) u1 t3) t6)→(ty3 g c3 t6 (THead (Bind Abst) u t0))
                                                                         end of H20
                                                                         by (pr0_comp . . H18 . . H19 .)
                                                                         we proved pr0 (THead (Bind b) u1 t3) (THead (Bind b) u2 t4)
                                                                         by (H20 . H4 . previous)
                                                                         we proved ty3 g c2 (THead (Bind b) u2 t4) (THead (Bind Abst) u t0)
                                                                         by (ty3_correct . . . . previous)
                                                                         we proved ex T λt:T.ty3 g c2 (THead (Bind Abst) u t0) t
                                                                         we proceed by induction on the previous result to prove 
                                                                            ty3
                                                                              g
                                                                              c2
                                                                              THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                              THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                            case ex_intro : x:T H22:ty3 g c2 (THead (Bind Abst) u t0) x ⇒
                                                                               the thesis becomes 
                                                                               ty3
                                                                                 g
                                                                                 c2
                                                                                 THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                 THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                  (H23) consider H22
                                                                                  by (ty3_gen_bind . . . . . . H23)
                                                                                  we proved 
                                                                                     ex3_2
                                                                                       T
                                                                                       T
                                                                                       λt2:T.λ:T.pc3 c2 (THead (Bind Abst) u t2) x
                                                                                       λ:T.λt:T.ty3 g c2 u t
                                                                                       λt2:T.λ:T.ty3 g (CHead c2 (Bind Abst) u) t0 t2
                                                                                  we proceed by induction on the previous result to prove 
                                                                                     ty3
                                                                                       g
                                                                                       c2
                                                                                       THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                       THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                     case ex3_2_intro : x0:T x1:T :pc3 c2 (THead (Bind Abst) u x0) x H25:ty3 g c2 u x1 H26:ty3 g (CHead c2 (Bind Abst) u) t0 x0 ⇒
                                                                                        the thesis becomes 
                                                                                        ty3
                                                                                          g
                                                                                          c2
                                                                                          THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                          THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                           by (pr0_comp . . H18 . . H19 .)
                                                                                           we proved pr0 (THead (Bind b) u1 t3) (THead (Bind b) u2 t4)
                                                                                           by (H20 . H4 . previous)
                                                                                           we proved ty3 g c2 (THead (Bind b) u2 t4) (THead (Bind Abst) u t0)
                                                                                           by (ty3_gen_bind . . . . . . previous)
                                                                                           we proved 
                                                                                              ex3_2
                                                                                                T
                                                                                                T
                                                                                                λt2:T.λ:T.pc3 c2 (THead (Bind b) u2 t2) (THead (Bind Abst) u t0)
                                                                                                λ:T.λt:T.ty3 g c2 u2 t
                                                                                                λt2:T.λ:T.ty3 g (CHead c2 (Bind b) u2) t4 t2
                                                                                           we proceed by induction on the previous result to prove 
                                                                                              ty3
                                                                                                g
                                                                                                c2
                                                                                                THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                                THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                              case ex3_2_intro : x2:T x3:T H27:pc3 c2 (THead (Bind b) u2 x2) (THead (Bind Abst) u t0) H28:ty3 g c2 u2 x3 H29:ty3 g (CHead c2 (Bind b) u2) t4 x2 ⇒
                                                                                                 the thesis becomes 
                                                                                                 ty3
                                                                                                   g
                                                                                                   c2
                                                                                                   THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                                   THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                    (H30) 
                                                                                                       by (lift_bind . . . . .)
                                                                                                       we proved 
                                                                                                          eq
                                                                                                            T
                                                                                                            lift (S O) O (THead (Bind Abst) u t0)
                                                                                                            THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                       we proceed by induction on the previous result to prove 
                                                                                                          pc3
                                                                                                            CHead c2 (Bind b) u2
                                                                                                            x2
                                                                                                            THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                          case refl_equal : ⇒
                                                                                                             the thesis becomes pc3 (CHead c2 (Bind b) u2) x2 (lift (S O) O (THead (Bind Abst) u t0))
                                                                                                                by (pc3_gen_not_abst . H16 . . . . . H27)
pc3 (CHead c2 (Bind b) u2) x2 (lift (S O) O (THead (Bind Abst) u t0))

                                                                                                          pc3
                                                                                                            CHead c2 (Bind b) u2
                                                                                                            x2
                                                                                                            THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                    end of H30
                                                                                                    (H31) 
                                                                                                       by (lift_bind . . . . .)
                                                                                                       we proved 
                                                                                                          eq
                                                                                                            T
                                                                                                            lift (S O) O (THead (Bind Abst) u t0)
                                                                                                            THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                       we proceed by induction on the previous result to prove 
                                                                                                          ty3
                                                                                                            g
                                                                                                            CHead c2 (Bind b) u2
                                                                                                            THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                            lift (S O) O x
                                                                                                          case refl_equal : ⇒
                                                                                                             the thesis becomes 
                                                                                                             ty3
                                                                                                               g
                                                                                                               CHead c2 (Bind b) u2
                                                                                                               lift (S O) O (THead (Bind Abst) u t0)
                                                                                                               lift (S O) O x
                                                                                                                by (drop_refl .)
                                                                                                                we proved drop O O c2 c2
                                                                                                                that is equivalent to drop (r (Bind b) O) O c2 c2
                                                                                                                by (drop_drop . . . . previous .)
                                                                                                                we proved drop (S O) O (CHead c2 (Bind b) u2) c2
                                                                                                                by (ty3_lift . . . . H22 . . . previous)

                                                                                                                   ty3
                                                                                                                     g
                                                                                                                     CHead c2 (Bind b) u2
                                                                                                                     lift (S O) O (THead (Bind Abst) u t0)
                                                                                                                     lift (S O) O x

                                                                                                          ty3
                                                                                                            g
                                                                                                            CHead c2 (Bind b) u2
                                                                                                            THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                            lift (S O) O x
                                                                                                    end of H31
                                                                                                    by (ty3_gen_bind . . . . . . H31)
                                                                                                    we proved 
                                                                                                       ex3_2
                                                                                                         T
                                                                                                         T
                                                                                                         λt2:T
                                                                                                           .λ:T
                                                                                                             .pc3
                                                                                                               CHead c2 (Bind b) u2
                                                                                                               THead (Bind Abst) (lift (S O) O u) t2
                                                                                                               lift (S O) O x
                                                                                                         λ:T.λt:T.ty3 g (CHead c2 (Bind b) u2) (lift (S O) O u) t
                                                                                                         λt2:T
                                                                                                           .λ:T
                                                                                                             .ty3
                                                                                                               g
                                                                                                               CHead (CHead c2 (Bind b) u2) (Bind Abst) (lift (S O) O u)
                                                                                                               lift (S O) (S O) t0
                                                                                                               t2
                                                                                                    we proceed by induction on the previous result to prove 
                                                                                                       ty3
                                                                                                         g
                                                                                                         c2
                                                                                                         THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                                         THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                       case ex3_2_intro : x4:T x5:T :pc3 (CHead c2 (Bind b) u2) (THead (Bind Abst) (lift (S O) O u) x4) (lift (S O) O x) H33:ty3 g (CHead c2 (Bind b) u2) (lift (S O) O u) x5 H34:ty3 g (CHead (CHead c2 (Bind b) u2) (Bind Abst) (lift (S O) O u)) (lift (S O) (S O) t0) x4 ⇒
                                                                                                          the thesis becomes 
                                                                                                          ty3
                                                                                                            g
                                                                                                            c2
                                                                                                            THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                                            THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                             (h1) 
                                                                                                                (h1) 
                                                                                                                   by (pr0_refl .)
                                                                                                                   we proved pr0 w w
                                                                                                                   by (H1 . H4 . previous)
ty3 g c2 w u
                                                                                                                end of h1
                                                                                                                (h2) 
                                                                                                                   by (ty3_bind . . . . H25 . . . H26)
ty3 g c2 (THead (Bind Abst) u t0) (THead (Bind Abst) u x0)
                                                                                                                end of h2
                                                                                                                by (ty3_appl . . . . h1 . . h2)

                                                                                                                   ty3
                                                                                                                     g
                                                                                                                     c2
                                                                                                                     THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                     THead (Flat Appl) w (THead (Bind Abst) u x0)
                                                                                                             end of h1
                                                                                                             (h2) 
                                                                                                                (h1) 
                                                                                                                   (h1) by (H1 . H4 . H17) we proved ty3 g c2 v2 u
                                                                                                                   (h2) 
                                                                                                                      by (drop_refl .)
                                                                                                                      we proved drop O O c2 c2
                                                                                                                      that is equivalent to drop (r (Bind b) O) O c2 c2
                                                                                                                      by (drop_drop . . . . previous .)
drop (S O) O (CHead c2 (Bind b) u2) c2
                                                                                                                   end of h2
                                                                                                                   by (ty3_lift . . . . h1 . . . h2)
ty3 g (CHead c2 (Bind b) u2) (lift (S O) O v2) (lift (S O) O u)
                                                                                                                end of h1
                                                                                                                (h2) 
                                                                                                                   by (ty3_bind . . . . H33 . . . H34)
                                                                                                                   we proved 
                                                                                                                      ty3
                                                                                                                        g
                                                                                                                        CHead c2 (Bind b) u2
                                                                                                                        THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                                        THead (Bind Abst) (lift (S O) O u) x4
                                                                                                                   by (ty3_conv . . . . previous . . H29 H30)

                                                                                                                      ty3
                                                                                                                        g
                                                                                                                        CHead c2 (Bind b) u2
                                                                                                                        t4
                                                                                                                        THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                                end of h2
                                                                                                                by (ty3_appl . . . . h1 . . h2)
                                                                                                                we proved 
                                                                                                                   ty3
                                                                                                                     g
                                                                                                                     CHead c2 (Bind b) u2
                                                                                                                     THead (Flat Appl) (lift (S O) O v2) t4
                                                                                                                     THead
                                                                                                                       Flat Appl
                                                                                                                       lift (S O) O v2
                                                                                                                       THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                                by (ty3_bind . . . . H28 . . . previous)

                                                                                                                   ty3
                                                                                                                     g
                                                                                                                     c2
                                                                                                                     THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                                                     THead
                                                                                                                       Bind b
                                                                                                                       u2
                                                                                                                       THead
                                                                                                                         Flat Appl
                                                                                                                         lift (S O) O v2
                                                                                                                         THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                             end of h2
                                                                                                             (h3) 
                                                                                                                by (lift_bind . . . . .)
                                                                                                                we proved 
                                                                                                                   eq
                                                                                                                     T
                                                                                                                     lift (S O) O (THead (Bind Abst) u t0)
                                                                                                                     THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                                we proceed by induction on the previous result to prove 
                                                                                                                   pc3
                                                                                                                     c2
                                                                                                                     THead
                                                                                                                       Bind b
                                                                                                                       u2
                                                                                                                       THead
                                                                                                                         Flat Appl
                                                                                                                         lift (S O) O v2
                                                                                                                         THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                                     THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                   case refl_equal : ⇒
                                                                                                                      the thesis becomes 
                                                                                                                      pc3
                                                                                                                        c2
                                                                                                                        THead
                                                                                                                          Bind b
                                                                                                                          u2
                                                                                                                          THead
                                                                                                                            Flat Appl
                                                                                                                            lift (S O) O v2
                                                                                                                            lift (S O) O (THead (Bind Abst) u t0)
                                                                                                                        THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                         (h1) 
                                                                                                                            (h1) by (pr0_refl .) we proved pr0 v2 v2
                                                                                                                            (h2) by (pr0_refl .) we proved pr0 u2 u2
                                                                                                                            (h3) 
                                                                                                                               by (pr0_refl .)

                                                                                                                                  pr0
                                                                                                                                    lift (S O) O (THead (Bind Abst) u t0)
                                                                                                                                    lift (S O) O (THead (Bind Abst) u t0)
                                                                                                                            end of h3
                                                                                                                            by (pr0_upsilon . H16 . . h1 . . h2 . . h3)

                                                                                                                               pr0
                                                                                                                                 THead
                                                                                                                                   Flat Appl
                                                                                                                                   v2
                                                                                                                                   THead (Bind b) u2 (lift (S O) O (THead (Bind Abst) u t0))
                                                                                                                                 THead
                                                                                                                                   Bind b
                                                                                                                                   u2
                                                                                                                                   THead
                                                                                                                                     Flat Appl
                                                                                                                                     lift (S O) O v2
                                                                                                                                     lift (S O) O (THead (Bind Abst) u t0)
                                                                                                                         end of h1
                                                                                                                         (h2) 
                                                                                                                            (h1) 
                                                                                                                               by (pc1_pr0_x . . H17)
pc1 v2 w
                                                                                                                            end of h1
                                                                                                                            (h2) 
                                                                                                                               by (pr0_refl .)
                                                                                                                               we proved pr0 (THead (Bind Abst) u t0) (THead (Bind Abst) u t0)
                                                                                                                               by (pr0_zeta . H16 . . previous .)
                                                                                                                               we proved 
                                                                                                                                  pr0
                                                                                                                                    THead (Bind b) u2 (lift (S O) O (THead (Bind Abst) u t0))
                                                                                                                                    THead (Bind Abst) u t0
                                                                                                                               by (pc1_pr0_r . . previous)

                                                                                                                                  pc1
                                                                                                                                    THead (Bind b) u2 (lift (S O) O (THead (Bind Abst) u t0))
                                                                                                                                    THead (Bind Abst) u t0
                                                                                                                            end of h2
                                                                                                                            by (pc1_head . . h1 . . h2 .)

                                                                                                                               pc1
                                                                                                                                 THead
                                                                                                                                   Flat Appl
                                                                                                                                   v2
                                                                                                                                   THead (Bind b) u2 (lift (S O) O (THead (Bind Abst) u t0))
                                                                                                                                 THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                         end of h2
                                                                                                                         by (pc1_pr0_u2 . . h1 . h2)
                                                                                                                         we proved 
                                                                                                                            pc1
                                                                                                                              THead
                                                                                                                                Bind b
                                                                                                                                u2
                                                                                                                                THead
                                                                                                                                  Flat Appl
                                                                                                                                  lift (S O) O v2
                                                                                                                                  lift (S O) O (THead (Bind Abst) u t0)
                                                                                                                              THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                                         by (pc3_pc1 . . previous .)

                                                                                                                            pc3
                                                                                                                              c2
                                                                                                                              THead
                                                                                                                                Bind b
                                                                                                                                u2
                                                                                                                                THead
                                                                                                                                  Flat Appl
                                                                                                                                  lift (S O) O v2
                                                                                                                                  lift (S O) O (THead (Bind Abst) u t0)
                                                                                                                              THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                                                   pc3
                                                                                                                     c2
                                                                                                                     THead
                                                                                                                       Bind b
                                                                                                                       u2
                                                                                                                       THead
                                                                                                                         Flat Appl
                                                                                                                         lift (S O) O v2
                                                                                                                         THead (Bind Abst) (lift (S O) O u) (lift (S O) (S O) t0)
                                                                                                                     THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                                                             end of h3
                                                                                                             by (ty3_conv . . . . h1 . . h2 h3)

                                                                                                                ty3
                                                                                                                  g
                                                                                                                  c2
                                                                                                                  THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                                                  THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                                       ty3
                                                                                                         g
                                                                                                         c2
                                                                                                         THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                                         THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                              ty3
                                                                                                g
                                                                                                c2
                                                                                                THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                                THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                                     ty3
                                                                                       g
                                                                                       c2
                                                                                       THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                       THead (Flat Appl) w (THead (Bind Abst) u t0)
                                                                         we proved 
                                                                            ty3
                                                                              g
                                                                              c2
                                                                              THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                              THead (Flat Appl) w (THead (Bind Abst) u t0)

                                                                         not (eq B b Abst)
                                                                           →(pr0 w v2
                                                                                →(pr0 u1 u2
                                                                                     →(pr0 t3 t4
                                                                                          →(ty3
                                                                                               g
                                                                                               c2
                                                                                               THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)
                                                                                               THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                                             we proved 
                                                                not (eq B b Abst)
                                                                  →(pr0 w v2
                                                                       →(pr0 u1 u2
                                                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))

                                                             eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                                               →(not (eq B b Abst)
                                                                    →(pr0 w v2
                                                                         →(pr0 u1 u2
                                                                              →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))
                                                 we proved 
                                                    eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                                      →(not (eq B b Abst)
                                                           →(pr0 w v2
                                                                →(pr0 u1 u2
                                                                     →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))

                                                 eq T (THead (Bind b) u1 t3) v
                                                   →(eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                                        →(not (eq B b Abst)
                                                             →(pr0 w v2
                                                                  →(pr0 u1 u2
                                                                       →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))))

                                        eq T (THead (Bind b) u1 t3) v
                                          →(eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                               →(not (eq B b Abst)
                                                    →(pr0 v1 v2
                                                         →(pr0 u1 u2
                                                              →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))))
                                  end of h1
                                  (h2) 
                                     consider H12
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T>
                                            CASE THead (Flat Appl) v1 (THead (Bind b) u1 t3) OF
                                              TSort ⇒THead (Bind b) u1 t3
                                            | TLRef ⇒THead (Bind b) u1 t3
                                            | THead   t5⇒t5
                                          <λ:T.T>
                                            CASE THead (Flat Appl) w v OF
                                              TSort ⇒THead (Bind b) u1 t3
                                            | TLRef ⇒THead (Bind b) u1 t3
                                            | THead   t5⇒t5
eq T (THead (Bind b) u1 t3) v
                                  end of h2
                                  by (h1 h2)
                                  we proved 
                                     eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                       →(not (eq B b Abst)
                                            →(pr0 v1 v2
                                                 →(pr0 u1 u2
                                                      →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))))
                                  by (previous H11 H6 H7 H8 H9)
                                  we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                                  ∀H10:eq
                                               T
                                               THead (Flat Appl) v1 (THead (Bind b) u1 t3)
                                               THead (Flat Appl) w v
                                    .∀H11:eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t4)) t2
                                      .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                            case pr0_delta u1:T u2:T H6:pr0 u1 u2 t3:T t4:T H7:pr0 t3 t4 w0:T H8:subst0 O u2 t4 w0 ⇒
                               the thesis becomes 
                                     ∀H9:eq T (THead (Bind Abbr) u1 t3) (THead (Flat Appl) w v)
                                       .∀H10:eq T (THead (Bind Abbr) u2 w0) t2
                                         .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                                suppose H9: eq T (THead (Bind Abbr) u1 t3) (THead (Flat Appl) w v)
                                suppose H10: eq T (THead (Bind Abbr) u2 w0) t2
                                  (H11) 
                                     we proceed by induction on H9 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Flat Appl) w v OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Bind Abbr) u1 t3 OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Bind Abbr) u1 t3 OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False

                                        <λ:T.Prop>
                                          CASE THead (Flat Appl) w v OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                  end of H11
                                  consider H11
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Flat Appl) w v OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T (THead (Bind Abbr) u2 w0) t2
                                       →(pr0 u1 u2
                                            →(pr0 t3 t4
                                                 →(subst0 O u2 t4 w0)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                  we proved 
                                     eq T (THead (Bind Abbr) u2 w0) t2
                                       →(pr0 u1 u2
                                            →(pr0 t3 t4
                                                 →(subst0 O u2 t4 w0)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))))
                                  by (previous H10 H6 H7 H8)
                                  we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                                  ∀H9:eq T (THead (Bind Abbr) u1 t3) (THead (Flat Appl) w v)
                                    .∀H10:eq T (THead (Bind Abbr) u2 w0) t2
                                      .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
                            case pr0_zeta b:B H6:not (eq B b Abst) t3:T t4:T H7:pr0 t3 t4 u0:T ⇒
                               the thesis becomes 
                                     ∀H8:eq
                                                T
                                                THead (Bind b) u0 (lift (S O) O t3)
                                                THead (Flat Appl) w v
                                       .∀H9:(eq T t4 t2).(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                suppose H8: 
                                   eq
                                     T
                                     THead (Bind b) u0 (lift (S O) O t3)
                                     THead (Flat Appl) w v
                                suppose H9: eq T t4 t2
                                  (H10) 
                                     we proceed by induction on H8 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Flat Appl) w v OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Bind b) u0 (lift (S O) O t3) OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Bind b) u0 (lift (S O) O t3) OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False

                                        <λ:T.Prop>
                                          CASE THead (Flat Appl) w v OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                  end of H10
                                  consider H10
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Flat Appl) w v OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T t4 t2
                                       →(not (eq B b Abst)
                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                  we proved 
                                     eq T t4 t2
                                       →(not (eq B b Abst)
                                            →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                                  ∀H8:eq
                                             T
                                             THead (Bind b) u0 (lift (S O) O t3)
                                             THead (Flat Appl) w v
                                    .∀H9:(eq T t4 t2).(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                            case pr0_tau t3:T t4:T H6:pr0 t3 t4 u0:T ⇒
                               the thesis becomes 
                                     ∀H7:eq T (THead (Flat Cast) u0 t3) (THead (Flat Appl) w v)
                                       .∀H8:(eq T t4 t2).(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                suppose H7: eq T (THead (Flat Cast) u0 t3) (THead (Flat Appl) w v)
                                suppose H8: eq T t4 t2
                                  (H9) 
                                     we proceed by induction on H7 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Flat Appl) w v OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒
                                                <λ:K.Prop>
                                                  CASE k OF
                                                    Bind ⇒False
                                                  | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒False | Cast⇒True
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Flat Cast) u0 t3 OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒
                                                   <λ:K.Prop>
                                                     CASE k OF
                                                       Bind ⇒False
                                                     | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒False | Cast⇒True
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Flat Cast) u0 t3 OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒
                                                         <λ:K.Prop>
                                                           CASE k OF
                                                             Bind ⇒False
                                                           | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒False | Cast⇒True

                                        <λ:T.Prop>
                                          CASE THead (Flat Appl) w v OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒
                                                <λ:K.Prop>
                                                  CASE k OF
                                                    Bind ⇒False
                                                  | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒False | Cast⇒True
                                  end of H9
                                  consider H9
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Flat Appl) w v OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒
                                             <λ:K.Prop>
                                               CASE k OF
                                                 Bind ⇒False
                                               | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒False | Cast⇒True
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T t4 t2
                                       →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                  we proved 
                                     eq T t4 t2
                                       →(pr0 t3 t4)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                                  by (previous H8 H6)
                                  we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                                  ∀H7:eq T (THead (Flat Cast) u0 t3) (THead (Flat Appl) w v)
                                    .∀H8:(eq T t4 t2).(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))

                            eq T (THead (Flat Appl) w v) (THead (Flat Appl) w v)
                              →(eq T t2 t2)→(ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0)))
                      end of H6
                      (h1) 
                         by (refl_equal . .)
eq T (THead (Flat Appl) w v) (THead (Flat Appl) w v)
                      end of h1
                      (h2) 
                         by (refl_equal . .)
eq T t2 t2
                      end of h2
                      by (H6 h1 h2)
                      we proved ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))

                      ∀c2:C
                        .∀H4:wcpr0 c c2
                          .∀t2:T
                            .∀H5:pr0 (THead (Flat Appl) w v) t2
                              .ty3 g c2 t2 (THead (Flat Appl) w (THead (Bind Abst) u t0))
             case ty3_cast : c:C t2:T t3:T :ty3 g c t2 t3 t0:T :ty3 g c t3 t0 ⇒
                the thesis becomes ∀c2:C.∀H4:(wcpr0 c c2).∀t4:T.∀H5:(pr0 (THead (Flat Cast) t3 t2) t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                (H1) by induction hypothesis we know ∀c2:C.(wcpr0 c c2)→∀t4:T.(pr0 t2 t4)→(ty3 g c2 t4 t3)
                (H3) by induction hypothesis we know ∀c2:C.(wcpr0 c c2)→∀t4:T.(pr0 t3 t4)→(ty3 g c2 t4 t0)
                    assume c2: C
                    suppose H4: wcpr0 c c2
                    assume t4: T
                    suppose H5: pr0 (THead (Flat Cast) t3 t2) t4
                      (H6) 
                         by cases on H5 we prove 
                            eq T (THead (Flat Cast) t3 t2) (THead (Flat Cast) t3 t2)
                              →(eq T t4 t4)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                            case pr0_refl t5:T ⇒
                               the thesis becomes ∀H6:(eq T t5 (THead (Flat Cast) t3 t2)).∀H7:(eq T t5 t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                suppose H6: eq T t5 (THead (Flat Cast) t3 t2)
                                suppose H7: eq T t5 t4
                                  by (sym_eq . . . H6)
                                  we proved eq T (THead (Flat Cast) t3 t2) t5
                                  suppose H8: eq T (THead (Flat Cast) t3 t2) t4
                                     we proceed by induction on H8 to prove ty3 g c2 t4 (THead (Flat Cast) t0 t3)
                                        case refl_equal : ⇒
                                           the thesis becomes ty3 g c2 (THead (Flat Cast) t3 t2) (THead (Flat Cast) t0 t3)
                                              (h1) 
                                                 by (pr0_refl .)
                                                 we proved pr0 t2 t2
                                                 by (H1 . H4 . previous)
ty3 g c2 t2 t3
                                              end of h1
                                              (h2) 
                                                 by (pr0_refl .)
                                                 we proved pr0 t3 t3
                                                 by (H3 . H4 . previous)
ty3 g c2 t3 t0
                                              end of h2
                                              by (ty3_cast . . . . h1 . h2)
ty3 g c2 (THead (Flat Cast) t3 t2) (THead (Flat Cast) t0 t3)
                                     we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)
(eq T (THead (Flat Cast) t3 t2) t4)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  by (previous previous H7)
                                  we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)
∀H6:(eq T t5 (THead (Flat Cast) t3 t2)).∀H7:(eq T t5 t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                            case pr0_comp u1:T u2:T H6:pr0 u1 u2 t5:T t6:T H7:pr0 t5 t6 k:K ⇒
                               the thesis becomes 
                                     ∀H8:eq T (THead k u1 t5) (THead (Flat Cast) t3 t2)
                                       .∀H9:(eq T (THead k u2 t6) t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                suppose H8: eq T (THead k u1 t5) (THead (Flat Cast) t3 t2)
                                suppose H9: eq T (THead k u2 t6) t4
                                  (H10) 
                                     by (f_equal . . . . . H8)
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead k u1 t5 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                          <λ:T.T> CASE THead (Flat Cast) t3 t2 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7

                                        eq
                                          T
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7 (THead k u1 t5)
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                            THead (Flat Cast) t3 t2
                                  end of H10
                                  (h1) 
                                     (H11) 
                                        by (f_equal . . . . . H8)
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead k u1 t5 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Flat Cast) t3 t2 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7

                                           eq
                                             T
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7 (THead k u1 t5)
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                               THead (Flat Cast) t3 t2
                                     end of H11
                                     (h1) 
                                        (H12) 
                                           by (f_equal . . . . . H8)
                                           we proved 
                                              eq
                                                K
                                                <λ:T.K> CASE THead k u1 t5 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                                <λ:T.K> CASE THead (Flat Cast) t3 t2 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0

                                              eq
                                                K
                                                λe:T.<λ:T.K> CASE e OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0 (THead k u1 t5)
                                                λe:T.<λ:T.K> CASE e OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                                  THead (Flat Cast) t3 t2
                                        end of H12
                                        consider H12
                                        we proved 
                                           eq
                                             K
                                             <λ:T.K> CASE THead k u1 t5 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                             <λ:T.K> CASE THead (Flat Cast) t3 t2 OF TSort ⇒k | TLRef ⇒k | THead k0  ⇒k0
                                        that is equivalent to eq K k (Flat Cast)
                                        by (sym_eq . . . previous)
                                        we proved eq K (Flat Cast) k
                                        we proceed by induction on the previous result to prove 
                                           eq T u1 t3
                                             →(eq T t5 t2
                                                  →(eq T (THead k u2 t6) t4
                                                       →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))))
                                           case refl_equal : ⇒
                                              the thesis becomes 
                                              eq T u1 t3
                                                →(eq T t5 t2
                                                     →(eq T (THead (Flat Cast) u2 t6) t4
                                                          →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))))
                                                 suppose H13: eq T u1 t3
                                                    by (sym_eq . . . H13)
                                                    we proved eq T t3 u1
                                                    we proceed by induction on the previous result to prove 
                                                       eq T t5 t2
                                                         →(eq T (THead (Flat Cast) u2 t6) t4
                                                              →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3)))
                                                       case refl_equal : ⇒
                                                          the thesis becomes 
                                                          eq T t5 t2
                                                            →(eq T (THead (Flat Cast) u2 t6) t4
                                                                 →(pr0 t3 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3)))
                                                             suppose H14: eq T t5 t2
                                                                by (sym_eq . . . H14)
                                                                we proved eq T t2 t5
                                                                we proceed by induction on the previous result to prove 
                                                                   eq T (THead (Flat Cast) u2 t6) t4
                                                                     →(pr0 t3 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                                   case refl_equal : ⇒
                                                                      the thesis becomes 
                                                                      eq T (THead (Flat Cast) u2 t6) t4
                                                                        →(pr0 t3 u2)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                                         suppose H15: eq T (THead (Flat Cast) u2 t6) t4
                                                                            we proceed by induction on H15 to prove (pr0 t3 u2)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                                               case refl_equal : ⇒
                                                                                  the thesis becomes 
                                                                                  pr0 t3 u2
                                                                                    →(pr0 t2 t6)→(ty3 g c2 (THead (Flat Cast) u2 t6) (THead (Flat Cast) t0 t3))
                                                                                      suppose H16: pr0 t3 u2
                                                                                      suppose H17: pr0 t2 t6
                                                                                        by (pr0_refl .)
                                                                                        we proved pr0 t3 t3
                                                                                        by (H3 . H4 . previous)
                                                                                        we proved ty3 g c2 t3 t0
                                                                                        by (ty3_correct . . . . previous)
                                                                                        we proved ex T λt:T.ty3 g c2 t0 t
                                                                                        we proceed by induction on the previous result to prove ty3 g c2 (THead (Flat Cast) u2 t6) (THead (Flat Cast) t0 t3)
                                                                                           case ex_intro : x:T H18:ty3 g c2 t0 x ⇒
                                                                                              the thesis becomes ty3 g c2 (THead (Flat Cast) u2 t6) (THead (Flat Cast) t0 t3)
                                                                                                 (h1) 
                                                                                                    by (pr0_refl .)
                                                                                                    we proved pr0 t3 t3
                                                                                                    by (H3 . H4 . previous)
                                                                                                    we proved ty3 g c2 t3 t0
                                                                                                    by (ty3_cast . . . . previous . H18)
ty3 g c2 (THead (Flat Cast) t0 t3) (THead (Flat Cast) x t0)
                                                                                                 end of h1
                                                                                                 (h2) 
                                                                                                    (h1) 
                                                                                                       (h1) by (H3 . H4 . H16) we proved ty3 g c2 u2 t0
                                                                                                       (h2) by (H1 . H4 . H17) we proved ty3 g c2 t6 t3
                                                                                                       (h3) 
                                                                                                          by (pr2_free . . . H16)
                                                                                                          we proved pr2 c2 t3 u2
                                                                                                          by (pc3_pr2_r . . . previous)
pc3 c2 t3 u2
                                                                                                       end of h3
                                                                                                       by (ty3_conv . . . . h1 . . h2 h3)
ty3 g c2 t6 u2
                                                                                                    end of h1
                                                                                                    (h2) by (H3 . H4 . H16) we proved ty3 g c2 u2 t0
                                                                                                    by (ty3_cast . . . . h1 . h2)
ty3 g c2 (THead (Flat Cast) u2 t6) (THead (Flat Cast) t0 u2)
                                                                                                 end of h2
                                                                                                 (h3) 
                                                                                                    by (pr2_free . . . H16)
                                                                                                    we proved pr2 c2 t3 u2
                                                                                                    by (pr2_thin_dx . . . previous . .)
                                                                                                    we proved pr2 c2 (THead (Flat Cast) t0 t3) (THead (Flat Cast) t0 u2)
                                                                                                    by (pc3_pr2_r . . . previous)
                                                                                                    we proved pc3 c2 (THead (Flat Cast) t0 t3) (THead (Flat Cast) t0 u2)
                                                                                                    by (pc3_s . . . previous)
pc3 c2 (THead (Flat Cast) t0 u2) (THead (Flat Cast) t0 t3)
                                                                                                 end of h3
                                                                                                 by (ty3_conv . . . . h1 . . h2 h3)
ty3 g c2 (THead (Flat Cast) u2 t6) (THead (Flat Cast) t0 t3)
                                                                                        we proved ty3 g c2 (THead (Flat Cast) u2 t6) (THead (Flat Cast) t0 t3)

                                                                                        pr0 t3 u2
                                                                                          →(pr0 t2 t6)→(ty3 g c2 (THead (Flat Cast) u2 t6) (THead (Flat Cast) t0 t3))
                                                                            we proved (pr0 t3 u2)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))

                                                                            eq T (THead (Flat Cast) u2 t6) t4
                                                                              →(pr0 t3 u2)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                                we proved 
                                                                   eq T (THead (Flat Cast) u2 t6) t4
                                                                     →(pr0 t3 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))

                                                                eq T t5 t2
                                                                  →(eq T (THead (Flat Cast) u2 t6) t4
                                                                       →(pr0 t3 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3)))
                                                    we proved 
                                                       eq T t5 t2
                                                         →(eq T (THead (Flat Cast) u2 t6) t4
                                                              →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3)))

                                                    eq T u1 t3
                                                      →(eq T t5 t2
                                                           →(eq T (THead (Flat Cast) u2 t6) t4
                                                                →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))))

                                           eq T u1 t3
                                             →(eq T t5 t2
                                                  →(eq T (THead k u2 t6) t4
                                                       →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))))
                                     end of h1
                                     (h2) 
                                        consider H11
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead k u1 t5 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Flat Cast) t3 t2 OF TSort ⇒u1 | TLRef ⇒u1 | THead  t7 ⇒t7
eq T u1 t3
                                     end of h2
                                     by (h1 h2)

                                        eq T t5 t2
                                          →(eq T (THead k u2 t6) t4
                                               →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3)))
                                  end of h1
                                  (h2) 
                                     consider H10
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead k u1 t5 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                          <λ:T.T> CASE THead (Flat Cast) t3 t2 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
eq T t5 t2
                                  end of h2
                                  by (h1 h2)
                                  we proved 
                                     eq T (THead k u2 t6) t4
                                       →(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)

                                  ∀H8:eq T (THead k u1 t5) (THead (Flat Cast) t3 t2)
                                    .∀H9:(eq T (THead k u2 t6) t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                            case pr0_beta u:T v1:T v2:T H6:pr0 v1 v2 t5:T t6:T H7:pr0 t5 t6 ⇒
                               the thesis becomes 
                                     ∀H8:eq
                                                T
                                                THead (Flat Appl) v1 (THead (Bind Abst) u t5)
                                                THead (Flat Cast) t3 t2
                                       .∀H9:(eq T (THead (Bind Abbr) v2 t6) t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                suppose H8: 
                                   eq
                                     T
                                     THead (Flat Appl) v1 (THead (Bind Abst) u t5)
                                     THead (Flat Cast) t3 t2
                                suppose H9: eq T (THead (Bind Abbr) v2 t6) t4
                                  (H10) 
                                     we proceed by induction on H8 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Flat Cast) t3 t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒
                                                <λ:K.Prop>
                                                  CASE k OF
                                                    Bind ⇒False
                                                  | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Flat Appl) v1 (THead (Bind Abst) u t5) OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒
                                                   <λ:K.Prop>
                                                     CASE k OF
                                                       Bind ⇒False
                                                     | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Flat Appl) v1 (THead (Bind Abst) u t5) OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒
                                                         <λ:K.Prop>
                                                           CASE k OF
                                                             Bind ⇒False
                                                           | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False

                                        <λ:T.Prop>
                                          CASE THead (Flat Cast) t3 t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒
                                                <λ:K.Prop>
                                                  CASE k OF
                                                    Bind ⇒False
                                                  | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False
                                  end of H10
                                  consider H10
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Flat Cast) t3 t2 OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒
                                             <λ:K.Prop>
                                               CASE k OF
                                                 Bind ⇒False
                                               | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T (THead (Bind Abbr) v2 t6) t4
                                       →(pr0 v1 v2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  we proved 
                                     eq T (THead (Bind Abbr) v2 t6) t4
                                       →(pr0 v1 v2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)

                                  ∀H8:eq
                                             T
                                             THead (Flat Appl) v1 (THead (Bind Abst) u t5)
                                             THead (Flat Cast) t3 t2
                                    .∀H9:(eq T (THead (Bind Abbr) v2 t6) t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                            case pr0_upsilon b:B H6:not (eq B b Abst) v1:T v2:T H7:pr0 v1 v2 u1:T u2:T H8:pr0 u1 u2 t5:T t6:T H9:pr0 t5 t6 ⇒
                               the thesis becomes 
                                     ∀H10:eq
                                                  T
                                                  THead (Flat Appl) v1 (THead (Bind b) u1 t5)
                                                  THead (Flat Cast) t3 t2
                                       .∀H11:eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                         .ty3 g c2 t4 (THead (Flat Cast) t0 t3)
                                suppose H10: 
                                   eq
                                     T
                                     THead (Flat Appl) v1 (THead (Bind b) u1 t5)
                                     THead (Flat Cast) t3 t2
                                suppose H11: eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                  (H12) 
                                     we proceed by induction on H10 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Flat Cast) t3 t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒
                                                <λ:K.Prop>
                                                  CASE k OF
                                                    Bind ⇒False
                                                  | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Flat Appl) v1 (THead (Bind b) u1 t5) OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒
                                                   <λ:K.Prop>
                                                     CASE k OF
                                                       Bind ⇒False
                                                     | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Flat Appl) v1 (THead (Bind b) u1 t5) OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒
                                                         <λ:K.Prop>
                                                           CASE k OF
                                                             Bind ⇒False
                                                           | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False

                                        <λ:T.Prop>
                                          CASE THead (Flat Cast) t3 t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒
                                                <λ:K.Prop>
                                                  CASE k OF
                                                    Bind ⇒False
                                                  | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False
                                  end of H12
                                  consider H12
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Flat Cast) t3 t2 OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒
                                             <λ:K.Prop>
                                               CASE k OF
                                                 Bind ⇒False
                                               | Flat f⇒<λ:F.Prop> CASE f OF Appl⇒True | Cast⇒False
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                       →(not (eq B b Abst)
                                            →(pr0 v1 v2)→(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3)))
                                  we proved 
                                     eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                       →(not (eq B b Abst)
                                            →(pr0 v1 v2)→(pr0 u1 u2)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3)))
                                  by (previous H11 H6 H7 H8 H9)
                                  we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)

                                  ∀H10:eq
                                               T
                                               THead (Flat Appl) v1 (THead (Bind b) u1 t5)
                                               THead (Flat Cast) t3 t2
                                    .∀H11:eq T (THead (Bind b) u2 (THead (Flat Appl) (lift (S O) O v2) t6)) t4
                                      .ty3 g c2 t4 (THead (Flat Cast) t0 t3)
                            case pr0_delta u1:T u2:T H6:pr0 u1 u2 t5:T t6:T H7:pr0 t5 t6 w:T H8:subst0 O u2 t6 w ⇒
                               the thesis becomes 
                                     ∀H9:eq T (THead (Bind Abbr) u1 t5) (THead (Flat Cast) t3 t2)
                                       .∀H10:(eq T (THead (Bind Abbr) u2 w) t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                suppose H9: eq T (THead (Bind Abbr) u1 t5) (THead (Flat Cast) t3 t2)
                                suppose H10: eq T (THead (Bind Abbr) u2 w) t4
                                  (H11) 
                                     we proceed by induction on H9 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Flat Cast) t3 t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Bind Abbr) u1 t5 OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Bind Abbr) u1 t5 OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False

                                        <λ:T.Prop>
                                          CASE THead (Flat Cast) t3 t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                  end of H11
                                  consider H11
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Flat Cast) t3 t2 OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T (THead (Bind Abbr) u2 w) t4
                                       →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  we proved 
                                     eq T (THead (Bind Abbr) u2 w) t4
                                       →(pr0 u1 u2)→(pr0 t5 t6)→(subst0 O u2 t6 w)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  by (previous H10 H6 H7 H8)
                                  we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)

                                  ∀H9:eq T (THead (Bind Abbr) u1 t5) (THead (Flat Cast) t3 t2)
                                    .∀H10:(eq T (THead (Bind Abbr) u2 w) t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                            case pr0_zeta b:B H6:not (eq B b Abst) t5:T t6:T H7:pr0 t5 t6 u:T ⇒
                               the thesis becomes 
                                     ∀H8:eq T (THead (Bind b) u (lift (S O) O t5)) (THead (Flat Cast) t3 t2)
                                       .∀H9:(eq T t6 t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                suppose H8: 
                                   eq T (THead (Bind b) u (lift (S O) O t5)) (THead (Flat Cast) t3 t2)
                                suppose H9: eq T t6 t4
                                  (H10) 
                                     we proceed by induction on H8 to prove 
                                        <λ:T.Prop>
                                          CASE THead (Flat Cast) t3 t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                        case refl_equal : ⇒
                                           the thesis becomes 
                                           <λ:T.Prop>
                                             CASE THead (Bind b) u (lift (S O) O t5) OF
                                               TSort ⇒False
                                             | TLRef ⇒False
                                             | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                              consider I
                                              we proved True

                                                 <λ:T.Prop>
                                                   CASE THead (Bind b) u (lift (S O) O t5) OF
                                                     TSort ⇒False
                                                   | TLRef ⇒False
                                                   | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False

                                        <λ:T.Prop>
                                          CASE THead (Flat Cast) t3 t2 OF
                                            TSort ⇒False
                                          | TLRef ⇒False
                                          | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                  end of H10
                                  consider H10
                                  we proved 
                                     <λ:T.Prop>
                                       CASE THead (Flat Cast) t3 t2 OF
                                         TSort ⇒False
                                       | TLRef ⇒False
                                       | THead k  ⇒<λ:K.Prop> CASE k OF Bind ⇒True | Flat ⇒False
                                  that is equivalent to False
                                  we proceed by induction on the previous result to prove 
                                     eq T t6 t4
                                       →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  we proved 
                                     eq T t6 t4
                                       →(not (eq B b Abst))→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  by (previous H9 H6 H7)
                                  we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)

                                  ∀H8:eq T (THead (Bind b) u (lift (S O) O t5)) (THead (Flat Cast) t3 t2)
                                    .∀H9:(eq T t6 t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                            case pr0_tau t5:T t6:T H6:pr0 t5 t6 u:T ⇒
                               the thesis becomes 
                                     ∀H7:eq T (THead (Flat Cast) u t5) (THead (Flat Cast) t3 t2)
                                       .∀H8:(eq T t6 t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                suppose H7: eq T (THead (Flat Cast) u t5) (THead (Flat Cast) t3 t2)
                                suppose H8: eq T t6 t4
                                  (H9) 
                                     by (f_equal . . . . . H7)
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead (Flat Cast) u t5 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                          <λ:T.T> CASE THead (Flat Cast) t3 t2 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7

                                        eq
                                          T
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                            THead (Flat Cast) u t5
                                          λe:T.<λ:T.T> CASE e OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                            THead (Flat Cast) t3 t2
                                  end of H9
                                  (h1) 
                                     (H10) 
                                        by (f_equal . . . . . H7)
                                        we proved 
                                           eq
                                             T
                                             <λ:T.T> CASE THead (Flat Cast) u t5 OF TSort ⇒u | TLRef ⇒u | THead  t7 ⇒t7
                                             <λ:T.T> CASE THead (Flat Cast) t3 t2 OF TSort ⇒u | TLRef ⇒u | THead  t7 ⇒t7

                                           eq
                                             T
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u | TLRef ⇒u | THead  t7 ⇒t7
                                               THead (Flat Cast) u t5
                                             λe:T.<λ:T.T> CASE e OF TSort ⇒u | TLRef ⇒u | THead  t7 ⇒t7
                                               THead (Flat Cast) t3 t2
                                     end of H10
                                     consider H10
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead (Flat Cast) u t5 OF TSort ⇒u | TLRef ⇒u | THead  t7 ⇒t7
                                          <λ:T.T> CASE THead (Flat Cast) t3 t2 OF TSort ⇒u | TLRef ⇒u | THead  t7 ⇒t7
                                     that is equivalent to eq T u t3
                                     by (sym_eq . . . previous)
                                     we proved eq T t3 u
                                     we proceed by induction on the previous result to prove (eq T t5 t2)→(eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                        case refl_equal : ⇒
                                           the thesis becomes (eq T t5 t2)→(eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                              suppose H11: eq T t5 t2
                                                 by (sym_eq . . . H11)
                                                 we proved eq T t2 t5
                                                 we proceed by induction on the previous result to prove (eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                    case refl_equal : ⇒
                                                       the thesis becomes (eq T t6 t4)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                          suppose H12: eq T t6 t4
                                                             by (sym_eq . . . H12)
                                                             we proved eq T t4 t6
                                                             we proceed by induction on the previous result to prove (pr0 t2 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                                case refl_equal : ⇒
                                                                   the thesis becomes (pr0 t2 t4)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                                      suppose H13: pr0 t2 t4
                                                                         by (pr0_refl .)
                                                                         we proved pr0 t3 t3
                                                                         by (H3 . H4 . previous)
                                                                         we proved ty3 g c2 t3 t0
                                                                         by (ty3_correct . . . . previous)
                                                                         we proved ex T λt:T.ty3 g c2 t0 t
                                                                         we proceed by induction on the previous result to prove ty3 g c2 t4 (THead (Flat Cast) t0 t3)
                                                                            case ex_intro : x:T H14:ty3 g c2 t0 x ⇒
                                                                               the thesis becomes ty3 g c2 t4 (THead (Flat Cast) t0 t3)
                                                                                  (h1) 
                                                                                     by (pr0_refl .)
                                                                                     we proved pr0 t3 t3
                                                                                     by (H3 . H4 . previous)
                                                                                     we proved ty3 g c2 t3 t0
                                                                                     by (ty3_cast . . . . previous . H14)
ty3 g c2 (THead (Flat Cast) t0 t3) (THead (Flat Cast) x t0)
                                                                                  end of h1
                                                                                  (h2) by (H1 . H4 . H13) we proved ty3 g c2 t4 t3
                                                                                  (h3) 
                                                                                     by (pr0_refl .)
                                                                                     we proved pr0 t3 t3
                                                                                     by (pr0_tau . . previous .)
                                                                                     we proved pr0 (THead (Flat Cast) t0 t3) t3
                                                                                     by (pr2_free . . . previous)
                                                                                     we proved pr2 c2 (THead (Flat Cast) t0 t3) t3
                                                                                     by (pc3_pr2_x . . . previous)
pc3 c2 t3 (THead (Flat Cast) t0 t3)
                                                                                  end of h3
                                                                                  by (ty3_conv . . . . h1 . . h2 h3)
ty3 g c2 t4 (THead (Flat Cast) t0 t3)
                                                                         we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)
(pr0 t2 t4)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                             we proved (pr0 t2 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
(eq T t6 t4)→(pr0 t2 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                                 we proved (eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
(eq T t5 t2)→(eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
(eq T t5 t2)→(eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  end of h1
                                  (h2) 
                                     consider H9
                                     we proved 
                                        eq
                                          T
                                          <λ:T.T> CASE THead (Flat Cast) u t5 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
                                          <λ:T.T> CASE THead (Flat Cast) t3 t2 OF TSort ⇒t5 | TLRef ⇒t5 | THead   t7⇒t7
eq T t5 t2
                                  end of h2
                                  by (h1 h2)
                                  we proved (eq T t6 t4)→(pr0 t5 t6)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                                  by (previous H8 H6)
                                  we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)

                                  ∀H7:eq T (THead (Flat Cast) u t5) (THead (Flat Cast) t3 t2)
                                    .∀H8:(eq T t6 t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))

                            eq T (THead (Flat Cast) t3 t2) (THead (Flat Cast) t3 t2)
                              →(eq T t4 t4)→(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
                      end of H6
                      (h1) 
                         by (refl_equal . .)
eq T (THead (Flat Cast) t3 t2) (THead (Flat Cast) t3 t2)
                      end of h1
                      (h2) 
                         by (refl_equal . .)
eq T t4 t4
                      end of h2
                      by (H6 h1 h2)
                      we proved ty3 g c2 t4 (THead (Flat Cast) t0 t3)
∀c2:C.∀H4:(wcpr0 c c2).∀t4:T.∀H5:(pr0 (THead (Flat Cast) t3 t2) t4).(ty3 g c2 t4 (THead (Flat Cast) t0 t3))
          we proved ∀c2:C.(wcpr0 c1 c2)→∀t3:T.(pr0 t1 t3)→(ty3 g c2 t3 t)
       we proved ∀g:G.∀c1:C.∀t1:T.∀t:T.(ty3 g c1 t1 t)→∀c2:C.(wcpr0 c1 c2)→∀t3:T.(pr0 t1 t3)→(ty3 g c2 t3 t)