DEFINITION ty3_gen_appl()
TYPE =
       ∀g:G
         .∀c:C
           .∀w:T
             .∀v:T
               .∀x:T
                 .ty3 g c (THead (Flat Appl) w v) x
                   →(ex3_2
                        T
                        T
                        λu:T.λt:T.pc3 c (THead (Flat Appl) w (THead (Bind Abst) u t)) x
                        λu:T.λt:T.ty3 g c v (THead (Bind Abst) u t)
                        λu:T.λ:T.ty3 g c w u)
BODY =
        assume g: G
        assume c: C
        assume w: T
        assume v: T
        assume x: T
        suppose H: ty3 g c (THead (Flat Appl) w v) x
           assume y: T
           suppose H0: ty3 g c y x
             we proceed by induction on H0 to prove 
                eq T y (THead (Flat Appl) w v)
                  →(ex3_2
                       T
                       T
                       λu:T.λt1:T.pc3 c (THead (Flat Appl) w (THead (Bind Abst) u t1)) x
                       λu:T.λt1:T.ty3 g c v (THead (Bind Abst) u t1)
                       λu:T.λ:T.ty3 g c w u)
                case ty3_conv : c0:C t2:T t:T :ty3 g c0 t2 t u:T t1:T H3:ty3 g c0 u t1 H5:pc3 c0 t1 t2 ⇒
                   the thesis becomes 
                   ∀H6:eq T u (THead (Flat Appl) w v)
                     .ex3_2
                       T
                       T
                       λu0:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t2
                       λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                       λu0:T.λ:T.ty3 g c0 w u0
                   () by induction hypothesis we know 
                      eq T t2 (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u t0)) t
                             λu:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u t0)
                             λu:T.λ:T.ty3 g c0 w u)
                   (H4) by induction hypothesis we know 
                      eq T u (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu0:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t1
                             λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g c0 w u0)
                      suppose H6: eq T u (THead (Flat Appl) w v)
                         (H7) 
                            by (f_equal . . . . . H6)
                            we proved eq T u (THead (Flat Appl) w v)
eq T (λe:T.e u) (λe:T.e (THead (Flat Appl) w v))
                         end of H7
                         (H8) 
                            we proceed by induction on H7 to prove 
                               eq T (THead (Flat Appl) w v) (THead (Flat Appl) w v)
                                 →(ex3_2
                                      T
                                      T
                                      λu0:T.λt3:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t3)) t1
                                      λu0:T.λt3:T.ty3 g c0 v (THead (Bind Abst) u0 t3)
                                      λu0:T.λ:T.ty3 g c0 w u0)
                               case refl_equal : ⇒
                                  the thesis becomes the hypothesis H4

                               eq T (THead (Flat Appl) w v) (THead (Flat Appl) w v)
                                 →(ex3_2
                                      T
                                      T
                                      λu0:T.λt3:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t3)) t1
                                      λu0:T.λt3:T.ty3 g c0 v (THead (Bind Abst) u0 t3)
                                      λu0:T.λ:T.ty3 g c0 w u0)
                         end of H8
                         (H10) 
                            by (refl_equal . .)
                            we proved eq T (THead (Flat Appl) w v) (THead (Flat Appl) w v)
                            by (H8 previous)

                               ex3_2
                                 T
                                 T
                                 λu0:T.λt3:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t3)) t1
                                 λu0:T.λt3:T.ty3 g c0 v (THead (Bind Abst) u0 t3)
                                 λu0:T.λ:T.ty3 g c0 w u0
                         end of H10
                         we proceed by induction on H10 to prove 
                            ex3_2
                              T
                              T
                              λu0:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t2
                              λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                              λu0:T.λ:T.ty3 g c0 w u0
                            case ex3_2_intro : x0:T x1:T H11:pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) x0 x1)) t1 H12:ty3 g c0 v (THead (Bind Abst) x0 x1) H13:ty3 g c0 w x0 ⇒
                               the thesis becomes 
                               ex3_2
                                 T
                                 T
                                 λu0:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t2
                                 λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                                 λu0:T.λ:T.ty3 g c0 w u0
                                  by (pc3_t . . . H11 . H5)
                                  we proved pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) x0 x1)) t2
                                  by (ex3_2_intro . . . . . . . previous H12 H13)

                                     ex3_2
                                       T
                                       T
                                       λu0:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t2
                                       λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                                       λu0:T.λ:T.ty3 g c0 w u0
                         we proved 
                            ex3_2
                              T
                              T
                              λu0:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t2
                              λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                              λu0:T.λ:T.ty3 g c0 w u0

                         ∀H6:eq T u (THead (Flat Appl) w v)
                           .ex3_2
                             T
                             T
                             λu0:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t2
                             λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g c0 w u0
                case ty3_sort : c0:C m:nat ⇒
                   the thesis becomes 
                   ∀H1:eq T (TSort m) (THead (Flat Appl) w v)
                     .ex3_2
                       T
                       T
                       λu:T
                         .λt:T
                           .pc3
                             c0
                             THead (Flat Appl) w (THead (Bind Abst) u t)
                             TSort (next g m)
                       λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                       λu:T.λ:T.ty3 g c0 w u
                      suppose H1: eq T (TSort m) (THead (Flat Appl) w v)
                         (H2) 
                            we proceed by induction on H1 to prove 
                               <λ:T.Prop>
                                 CASE THead (Flat Appl) w v OF
                                   TSort ⇒True
                                 | TLRef ⇒False
                                 | THead   ⇒False
                               case refl_equal : ⇒
                                  the thesis becomes 
                                  <λ:T.Prop>
                                    CASE TSort m OF
                                      TSort ⇒True
                                    | TLRef ⇒False
                                    | THead   ⇒False
                                     consider I
                                     we proved True

                                        <λ:T.Prop>
                                          CASE TSort m OF
                                            TSort ⇒True
                                          | TLRef ⇒False
                                          | THead   ⇒False

                               <λ:T.Prop>
                                 CASE THead (Flat Appl) w v OF
                                   TSort ⇒True
                                 | TLRef ⇒False
                                 | THead   ⇒False
                         end of H2
                         consider H2
                         we proved 
                            <λ:T.Prop>
                              CASE THead (Flat Appl) w v OF
                                TSort ⇒True
                              | TLRef ⇒False
                              | THead   ⇒False
                         that is equivalent to False
                         we proceed by induction on the previous result to prove 
                            ex3_2
                              T
                              T
                              λu:T
                                .λt:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u t)
                                    TSort (next g m)
                              λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                              λu:T.λ:T.ty3 g c0 w u
                         we proved 
                            ex3_2
                              T
                              T
                              λu:T
                                .λt:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u t)
                                    TSort (next g m)
                              λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                              λu:T.λ:T.ty3 g c0 w u

                         ∀H1:eq T (TSort m) (THead (Flat Appl) w v)
                           .ex3_2
                             T
                             T
                             λu:T
                               .λt:T
                                 .pc3
                                   c0
                                   THead (Flat Appl) w (THead (Bind Abst) u t)
                                   TSort (next g m)
                             λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                             λu:T.λ:T.ty3 g c0 w u
                case ty3_abbr : n:nat c0:C d:C u:T :getl n c0 (CHead d (Bind Abbr) u) t:T :ty3 g d u t ⇒
                   the thesis becomes 
                   ∀H4:eq T (TLRef n) (THead (Flat Appl) w v)
                     .ex3_2
                       T
                       T
                       λu0:T
                         .λt0:T
                           .pc3
                             c0
                             THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                             lift (S n) O t
                       λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                       λu0:T.λ:T.ty3 g c0 w u0
                   () by induction hypothesis we know 
                      eq T u (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu0:T.λt0:T.pc3 d (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t
                             λu0:T.λt0:T.ty3 g d v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g d w u0)
                      suppose H4: eq T (TLRef n) (THead (Flat Appl) w v)
                         (H5) 
                            we proceed by induction on H4 to prove 
                               <λ:T.Prop>
                                 CASE THead (Flat Appl) w v OF
                                   TSort ⇒False
                                 | TLRef ⇒True
                                 | THead   ⇒False
                               case refl_equal : ⇒
                                  the thesis becomes 
                                  <λ:T.Prop>
                                    CASE TLRef n OF
                                      TSort ⇒False
                                    | TLRef ⇒True
                                    | THead   ⇒False
                                     consider I
                                     we proved True

                                        <λ:T.Prop>
                                          CASE TLRef n OF
                                            TSort ⇒False
                                          | TLRef ⇒True
                                          | THead   ⇒False

                               <λ:T.Prop>
                                 CASE THead (Flat Appl) w v OF
                                   TSort ⇒False
                                 | TLRef ⇒True
                                 | THead   ⇒False
                         end of H5
                         consider H5
                         we proved 
                            <λ:T.Prop>
                              CASE THead (Flat Appl) w v OF
                                TSort ⇒False
                              | TLRef ⇒True
                              | THead   ⇒False
                         that is equivalent to False
                         we proceed by induction on the previous result to prove 
                            ex3_2
                              T
                              T
                              λu0:T
                                .λt0:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                    lift (S n) O t
                              λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                              λu0:T.λ:T.ty3 g c0 w u0
                         we proved 
                            ex3_2
                              T
                              T
                              λu0:T
                                .λt0:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                    lift (S n) O t
                              λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                              λu0:T.λ:T.ty3 g c0 w u0

                         ∀H4:eq T (TLRef n) (THead (Flat Appl) w v)
                           .ex3_2
                             T
                             T
                             λu0:T
                               .λt0:T
                                 .pc3
                                   c0
                                   THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                   lift (S n) O t
                             λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g c0 w u0
                case ty3_abst : n:nat c0:C d:C u:T :getl n c0 (CHead d (Bind Abst) u) t:T :ty3 g d u t ⇒
                   the thesis becomes 
                   ∀H4:eq T (TLRef n) (THead (Flat Appl) w v)
                     .ex3_2
                       T
                       T
                       λu0:T
                         .λt0:T
                           .pc3
                             c0
                             THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                             lift (S n) O u
                       λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                       λu0:T.λ:T.ty3 g c0 w u0
                   () by induction hypothesis we know 
                      eq T u (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu0:T.λt0:T.pc3 d (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t
                             λu0:T.λt0:T.ty3 g d v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g d w u0)
                      suppose H4: eq T (TLRef n) (THead (Flat Appl) w v)
                         (H5) 
                            we proceed by induction on H4 to prove 
                               <λ:T.Prop>
                                 CASE THead (Flat Appl) w v OF
                                   TSort ⇒False
                                 | TLRef ⇒True
                                 | THead   ⇒False
                               case refl_equal : ⇒
                                  the thesis becomes 
                                  <λ:T.Prop>
                                    CASE TLRef n OF
                                      TSort ⇒False
                                    | TLRef ⇒True
                                    | THead   ⇒False
                                     consider I
                                     we proved True

                                        <λ:T.Prop>
                                          CASE TLRef n OF
                                            TSort ⇒False
                                          | TLRef ⇒True
                                          | THead   ⇒False

                               <λ:T.Prop>
                                 CASE THead (Flat Appl) w v OF
                                   TSort ⇒False
                                 | TLRef ⇒True
                                 | THead   ⇒False
                         end of H5
                         consider H5
                         we proved 
                            <λ:T.Prop>
                              CASE THead (Flat Appl) w v OF
                                TSort ⇒False
                              | TLRef ⇒True
                              | THead   ⇒False
                         that is equivalent to False
                         we proceed by induction on the previous result to prove 
                            ex3_2
                              T
                              T
                              λu0:T
                                .λt0:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                    lift (S n) O u
                              λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                              λu0:T.λ:T.ty3 g c0 w u0
                         we proved 
                            ex3_2
                              T
                              T
                              λu0:T
                                .λt0:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                    lift (S n) O u
                              λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                              λu0:T.λ:T.ty3 g c0 w u0

                         ∀H4:eq T (TLRef n) (THead (Flat Appl) w v)
                           .ex3_2
                             T
                             T
                             λu0:T
                               .λt0:T
                                 .pc3
                                   c0
                                   THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                   lift (S n) O u
                             λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g c0 w u0
                case ty3_bind : c0:C u:T t:T :ty3 g c0 u t b:B t1:T t2:T :ty3 g (CHead c0 (Bind b) u) t1 t2 ⇒
                   the thesis becomes 
                   ∀H5:eq T (THead (Bind b) u t1) (THead (Flat Appl) w v)
                     .ex3_2
                       T
                       T
                       λu0:T
                         .λt0:T
                           .pc3
                             c0
                             THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                             THead (Bind b) u t2
                       λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                       λu0:T.λ:T.ty3 g c0 w u0
                   () by induction hypothesis we know 
                      eq T u (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu0:T.λt0:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t0)) t
                             λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g c0 w u0)
                   () by induction hypothesis we know 
                      eq T t1 (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu0:T
                               .λt0:T
                                 .pc3
                                   CHead c0 (Bind b) u
                                   THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                   t2
                             λu0:T.λt0:T.ty3 g (CHead c0 (Bind b) u) v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g (CHead c0 (Bind b) u) w u0)
                      suppose H5: eq T (THead (Bind b) u t1) (THead (Flat Appl) w v)
                         (H6) 
                            we proceed by induction on H5 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) u t1 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 t1 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 H6
                         consider H6
                         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 
                            ex3_2
                              T
                              T
                              λu0:T
                                .λt0:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                    THead (Bind b) u t2
                              λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                              λu0:T.λ:T.ty3 g c0 w u0
                         we proved 
                            ex3_2
                              T
                              T
                              λu0:T
                                .λt0:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                    THead (Bind b) u t2
                              λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                              λu0:T.λ:T.ty3 g c0 w u0

                         ∀H5:eq T (THead (Bind b) u t1) (THead (Flat Appl) w v)
                           .ex3_2
                             T
                             T
                             λu0:T
                               .λt0:T
                                 .pc3
                                   c0
                                   THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                   THead (Bind b) u t2
                             λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g c0 w u0
                case ty3_appl : c0:C w0:T u:T H1:ty3 g c0 w0 u v0:T t:T H3:ty3 g c0 v0 (THead (Bind Abst) u t) ⇒
                   the thesis becomes 
                   ∀H5:eq T (THead (Flat Appl) w0 v0) (THead (Flat Appl) w v)
                     .ex3_2
                       T
                       T
                       λu0:T
                         .λt1:T
                           .pc3
                             c0
                             THead (Flat Appl) w (THead (Bind Abst) u0 t1)
                             THead (Flat Appl) w0 (THead (Bind Abst) u t)
                       λu0:T.λt1:T.ty3 g c0 v (THead (Bind Abst) u0 t1)
                       λu0:T.λ:T.ty3 g c0 w u0
                   (H2) by induction hypothesis we know 
                      eq T w0 (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu0:T.λt:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u0 t)) u
                             λu0:T.λt:T.ty3 g c0 v (THead (Bind Abst) u0 t)
                             λu0:T.λ:T.ty3 g c0 w u0)
                   (H4) by induction hypothesis we know 
                      eq T v0 (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu0:T
                               .λt0:T
                                 .pc3
                                   c0
                                   THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                   THead (Bind Abst) u t
                             λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                             λu0:T.λ:T.ty3 g c0 w u0)
                      suppose H5: eq T (THead (Flat Appl) w0 v0) (THead (Flat Appl) w v)
                         (H6) 
                            by (f_equal . . . . . H5)
                            we proved 
                               eq
                                 T
                                 <λ:T.T> CASE THead (Flat Appl) w0 v0 OF TSort ⇒w0 | TLRef ⇒w0 | THead  t0 ⇒t0
                                 <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒w0 | TLRef ⇒w0 | THead  t0 ⇒t0

                               eq
                                 T
                                 λe:T.<λ:T.T> CASE e OF TSort ⇒w0 | TLRef ⇒w0 | THead  t0 ⇒t0
                                   THead (Flat Appl) w0 v0
                                 λe:T.<λ:T.T> CASE e OF TSort ⇒w0 | TLRef ⇒w0 | THead  t0 ⇒t0
                                   THead (Flat Appl) w v
                         end of H6
                         (h1) 
                            (H7) 
                               by (f_equal . . . . . H5)
                               we proved 
                                  eq
                                    T
                                    <λ:T.T> CASE THead (Flat Appl) w0 v0 OF TSort ⇒v0 | TLRef ⇒v0 | THead   t0⇒t0
                                    <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒v0 | TLRef ⇒v0 | THead   t0⇒t0

                                  eq
                                    T
                                    λe:T.<λ:T.T> CASE e OF TSort ⇒v0 | TLRef ⇒v0 | THead   t0⇒t0
                                      THead (Flat Appl) w0 v0
                                    λe:T.<λ:T.T> CASE e OF TSort ⇒v0 | TLRef ⇒v0 | THead   t0⇒t0
                                      THead (Flat Appl) w v
                            end of H7
                            suppose H8: eq T w0 w
                               (H10) 
                                  consider H7
                                  we proved 
                                     eq
                                       T
                                       <λ:T.T> CASE THead (Flat Appl) w0 v0 OF TSort ⇒v0 | TLRef ⇒v0 | THead   t0⇒t0
                                       <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒v0 | TLRef ⇒v0 | THead   t0⇒t0
                                  that is equivalent to eq T v0 v
                                  we proceed by induction on the previous result to prove ty3 g c0 v (THead (Bind Abst) u t)
                                     case refl_equal : ⇒
                                        the thesis becomes the hypothesis H3
ty3 g c0 v (THead (Bind Abst) u t)
                               end of H10
                               (H12) 
                                  we proceed by induction on H8 to prove ty3 g c0 w u
                                     case refl_equal : ⇒
                                        the thesis becomes the hypothesis H1
ty3 g c0 w u
                               end of H12
                               by (pc3_refl . .)
                               we proved 
                                  pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u t)
                                    THead (Flat Appl) w (THead (Bind Abst) u t)
                               by (ex3_2_intro . . . . . . . previous H10 H12)
                               we proved 
                                  ex3_2
                                    T
                                    T
                                    λu0:T
                                      .λt0:T
                                        .pc3
                                          c0
                                          THead (Flat Appl) w (THead (Bind Abst) u0 t0)
                                          THead (Flat Appl) w (THead (Bind Abst) u t)
                                    λu0:T.λt0:T.ty3 g c0 v (THead (Bind Abst) u0 t0)
                                    λu0:T.λ:T.ty3 g c0 w u0
                               by (eq_ind_r . . . previous . H8)
                               we proved 
                                  ex3_2
                                    T
                                    T
                                    λu0:T
                                      .λt1:T
                                        .pc3
                                          c0
                                          THead (Flat Appl) w (THead (Bind Abst) u0 t1)
                                          THead (Flat Appl) w0 (THead (Bind Abst) u t)
                                    λu0:T.λt1:T.ty3 g c0 v (THead (Bind Abst) u0 t1)
                                    λu0:T.λ:T.ty3 g c0 w u0

                               eq T w0 w
                                 →(ex3_2
                                      T
                                      T
                                      λu0:T
                                        .λt1:T
                                          .pc3
                                            c0
                                            THead (Flat Appl) w (THead (Bind Abst) u0 t1)
                                            THead (Flat Appl) w0 (THead (Bind Abst) u t)
                                      λu0:T.λt1:T.ty3 g c0 v (THead (Bind Abst) u0 t1)
                                      λu0:T.λ:T.ty3 g c0 w u0)
                         end of h1
                         (h2) 
                            consider H6
                            we proved 
                               eq
                                 T
                                 <λ:T.T> CASE THead (Flat Appl) w0 v0 OF TSort ⇒w0 | TLRef ⇒w0 | THead  t0 ⇒t0
                                 <λ:T.T> CASE THead (Flat Appl) w v OF TSort ⇒w0 | TLRef ⇒w0 | THead  t0 ⇒t0
eq T w0 w
                         end of h2
                         by (h1 h2)
                         we proved 
                            ex3_2
                              T
                              T
                              λu0:T
                                .λt1:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u0 t1)
                                    THead (Flat Appl) w0 (THead (Bind Abst) u t)
                              λu0:T.λt1:T.ty3 g c0 v (THead (Bind Abst) u0 t1)
                              λu0:T.λ:T.ty3 g c0 w u0

                         ∀H5:eq T (THead (Flat Appl) w0 v0) (THead (Flat Appl) w v)
                           .ex3_2
                             T
                             T
                             λu0:T
                               .λt1:T
                                 .pc3
                                   c0
                                   THead (Flat Appl) w (THead (Bind Abst) u0 t1)
                                   THead (Flat Appl) w0 (THead (Bind Abst) u t)
                             λu0:T.λt1:T.ty3 g c0 v (THead (Bind Abst) u0 t1)
                             λu0:T.λ:T.ty3 g c0 w u0
                case ty3_cast : c0:C t1:T t2:T :ty3 g c0 t1 t2 t0:T :ty3 g c0 t2 t0 ⇒
                   the thesis becomes 
                   ∀H5:eq T (THead (Flat Cast) t2 t1) (THead (Flat Appl) w v)
                     .ex3_2
                       T
                       T
                       λu:T
                         .λt:T
                           .pc3
                             c0
                             THead (Flat Appl) w (THead (Bind Abst) u t)
                             THead (Flat Cast) t0 t2
                       λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                       λu:T.λ:T.ty3 g c0 w u
                   () by induction hypothesis we know 
                      eq T t1 (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu:T.λt:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u t)) t2
                             λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                             λu:T.λ:T.ty3 g c0 w u)
                   () by induction hypothesis we know 
                      eq T t2 (THead (Flat Appl) w v)
                        →(ex3_2
                             T
                             T
                             λu:T.λt:T.pc3 c0 (THead (Flat Appl) w (THead (Bind Abst) u t)) t0
                             λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                             λu:T.λ:T.ty3 g c0 w u)
                      suppose H5: eq T (THead (Flat Cast) t2 t1) (THead (Flat Appl) w v)
                         (H6) 
                            we proceed by induction on H5 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) t2 t1 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) t2 t1 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 H6
                         consider H6
                         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 
                            ex3_2
                              T
                              T
                              λu:T
                                .λt:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u t)
                                    THead (Flat Cast) t0 t2
                              λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                              λu:T.λ:T.ty3 g c0 w u
                         we proved 
                            ex3_2
                              T
                              T
                              λu:T
                                .λt:T
                                  .pc3
                                    c0
                                    THead (Flat Appl) w (THead (Bind Abst) u t)
                                    THead (Flat Cast) t0 t2
                              λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                              λu:T.λ:T.ty3 g c0 w u

                         ∀H5:eq T (THead (Flat Cast) t2 t1) (THead (Flat Appl) w v)
                           .ex3_2
                             T
                             T
                             λu:T
                               .λt:T
                                 .pc3
                                   c0
                                   THead (Flat Appl) w (THead (Bind Abst) u t)
                                   THead (Flat Cast) t0 t2
                             λu:T.λt:T.ty3 g c0 v (THead (Bind Abst) u t)
                             λu:T.λ:T.ty3 g c0 w u
             we proved 
                eq T y (THead (Flat Appl) w v)
                  →(ex3_2
                       T
                       T
                       λu:T.λt1:T.pc3 c (THead (Flat Appl) w (THead (Bind Abst) u t1)) x
                       λu:T.λt1:T.ty3 g c v (THead (Bind Abst) u t1)
                       λu:T.λ:T.ty3 g c w u)
          we proved 
             ∀y:T
               .ty3 g c y x
                 →(eq T y (THead (Flat Appl) w v)
                      →(ex3_2
                           T
                           T
                           λu:T.λt1:T.pc3 c (THead (Flat Appl) w (THead (Bind Abst) u t1)) x
                           λu:T.λt1:T.ty3 g c v (THead (Bind Abst) u t1)
                           λu:T.λ:T.ty3 g c w u))
          by (insert_eq . . . . previous H)
          we proved 
             ex3_2
               T
               T
               λu:T.λt0:T.pc3 c (THead (Flat Appl) w (THead (Bind Abst) u t0)) x
               λu:T.λt0:T.ty3 g c v (THead (Bind Abst) u t0)
               λu:T.λ:T.ty3 g c w u
       we proved 
          ∀g:G
            .∀c:C
              .∀w:T
                .∀v:T
                  .∀x:T
                    .ty3 g c (THead (Flat Appl) w v) x
                      →(ex3_2
                           T
                           T
                           λu:T.λt0:T.pc3 c (THead (Flat Appl) w (THead (Bind Abst) u t0)) x
                           λu:T.λt0:T.ty3 g c v (THead (Bind Abst) u t0)
                           λu:T.λ:T.ty3 g c w u)