DEFINITION wf3_gen_head2()
TYPE =
       g:G.x:C.c:C.v:T.k:K.(wf3 g x (CHead c k v))(ex B λb:B.eq K k (Bind b))
BODY =
        assume gG
        assume xC
        assume cC
        assume vT
        assume kK
        suppose Hwf3 g x (CHead c k v)
           assume yC
           suppose H0wf3 g x y
             we proceed by induction on H0 to prove (eq C y (CHead c k v))(ex B λb:B.eq K k (Bind b))
                case wf3_sort : m:nat 
                   the thesis becomes H1:(eq C (CSort m) (CHead c k v)).(ex B λb:B.eq K k (Bind b))
                      suppose H1eq C (CSort m) (CHead c k v)
                         (H2
                            we proceed by induction on H1 to prove <λ:C.Prop> CASE CHead c k v OF CSort True | CHead   False
                               case refl_equal : 
                                  the thesis becomes <λ:C.Prop> CASE CSort m OF CSort True | CHead   False
                                     consider I
                                     we proved True
<λ:C.Prop> CASE CSort m OF CSort True | CHead   False
<λ:C.Prop> CASE CHead c k v OF CSort True | CHead   False
                         end of H2
                         consider H2
                         we proved <λ:C.Prop> CASE CHead c k v OF CSort True | CHead   False
                         that is equivalent to False
                         we proceed by induction on the previous result to prove ex B λb:B.eq K k (Bind b)
                         we proved ex B λb:B.eq K k (Bind b)
H1:(eq C (CSort m) (CHead c k v)).(ex B λb:B.eq K k (Bind b))
                case wf3_bind : c1:C c2:C H1:wf3 g c1 c2 u:T t:T H3:ty3 g c1 u t b:B 
                   the thesis becomes 
                   H4:(eq C (CHead c2 (Bind b) u) (CHead c k v)).(ex B λb0:B.eq K k (Bind b0))
                   (H2) by induction hypothesis we know (eq C c2 (CHead c k v))(ex B λb:B.eq K k (Bind b))
                      suppose H4eq C (CHead c2 (Bind b) u) (CHead c k v)
                         (H5
                            by (f_equal . . . . . H4)
                            we proved 
                               eq
                                 C
                                 <λ:C.C> CASE CHead c2 (Bind b) u OF CSort c2 | CHead c0  c0
                                 <λ:C.C> CASE CHead c k v OF CSort c2 | CHead c0  c0

                               eq
                                 C
                                 λe:C.<λ:C.C> CASE e OF CSort c2 | CHead c0  c0 (CHead c2 (Bind b) u)
                                 λe:C.<λ:C.C> CASE e OF CSort c2 | CHead c0  c0 (CHead c k v)
                         end of H5
                         (h1
                            (H6
                               by (f_equal . . . . . H4)
                               we proved 
                                  eq
                                    K
                                    <λ:C.K> CASE CHead c2 (Bind b) u OF CSort Bind b | CHead  k0 k0
                                    <λ:C.K> CASE CHead c k v OF CSort Bind b | CHead  k0 k0

                                  eq
                                    K
                                    λe:C.<λ:C.K> CASE e OF CSort Bind b | CHead  k0 k0
                                      CHead c2 (Bind b) u
                                    λe:C.<λ:C.K> CASE e OF CSort Bind b | CHead  k0 k0 (CHead c k v)
                            end of H6
                            (h1
                               (H7
                                  by (f_equal . . . . . H4)
                                  we proved 
                                     eq
                                       T
                                       <λ:C.T> CASE CHead c2 (Bind b) u OF CSort u | CHead   t0t0
                                       <λ:C.T> CASE CHead c k v OF CSort u | CHead   t0t0

                                     eq
                                       T
                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   t0t0 (CHead c2 (Bind b) u)
                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   t0t0 (CHead c k v)
                               end of H7
                                suppose H8eq K (Bind b) k
                                suppose H9eq C c2 c
                                  (H11
                                     we proceed by induction on H9 to prove (eq C c (CHead c k v))(ex B λb0:B.eq K k (Bind b0))
                                        case refl_equal : 
                                           the thesis becomes the hypothesis H2
(eq C c (CHead c k v))(ex B λb0:B.eq K k (Bind b0))
                                  end of H11
                                  we proceed by induction on H8 to prove ex B λb0:B.eq K k (Bind b0)
                                     case refl_equal : 
                                        the thesis becomes ex B λb0:B.eq K (Bind b) (Bind b0)
                                           by (refl_equal . .)
                                           we proved eq K (Bind b) (Bind b)
                                           by (ex_intro . . . previous)
ex B λb0:B.eq K (Bind b) (Bind b0)
                                  we proved ex B λb0:B.eq K k (Bind b0)
(eq K (Bind b) k)(eq C c2 c)(ex B λb0:B.eq K k (Bind b0))
                            end of h1
                            (h2
                               consider H6
                               we proved 
                                  eq
                                    K
                                    <λ:C.K> CASE CHead c2 (Bind b) u OF CSort Bind b | CHead  k0 k0
                                    <λ:C.K> CASE CHead c k v OF CSort Bind b | CHead  k0 k0
eq K (Bind b) k
                            end of h2
                            by (h1 h2)
(eq C c2 c)(ex B λb0:B.eq K k (Bind b0))
                         end of h1
                         (h2
                            consider H5
                            we proved 
                               eq
                                 C
                                 <λ:C.C> CASE CHead c2 (Bind b) u OF CSort c2 | CHead c0  c0
                                 <λ:C.C> CASE CHead c k v OF CSort c2 | CHead c0  c0
eq C c2 c
                         end of h2
                         by (h1 h2)
                         we proved ex B λb0:B.eq K k (Bind b0)

                         H4:(eq C (CHead c2 (Bind b) u) (CHead c k v)).(ex B λb0:B.eq K k (Bind b0))
                case wf3_void : c1:C c2:C H1:wf3 g c1 c2 u:T :t:T.(ty3 g c1 u t)False :B 
                   the thesis becomes 
                   H4:eq C (CHead c2 (Bind Void) (TSort O)) (CHead c k v)
                     .ex B λb0:B.eq K k (Bind b0)
                   (H2) by induction hypothesis we know (eq C c2 (CHead c k v))(ex B λb:B.eq K k (Bind b))
                      suppose H4eq C (CHead c2 (Bind Void) (TSort O)) (CHead c k v)
                         (H5
                            by (f_equal . . . . . H4)
                            we proved 
                               eq
                                 C
                                 <λ:C.C> CASE CHead c2 (Bind Void) (TSort O) OF CSort c2 | CHead c0  c0
                                 <λ:C.C> CASE CHead c k v OF CSort c2 | CHead c0  c0

                               eq
                                 C
                                 λe:C.<λ:C.C> CASE e OF CSort c2 | CHead c0  c0
                                   CHead c2 (Bind Void) (TSort O)
                                 λe:C.<λ:C.C> CASE e OF CSort c2 | CHead c0  c0 (CHead c k v)
                         end of H5
                         (h1
                            (H6
                               by (f_equal . . . . . H4)
                               we proved 
                                  eq
                                    K
                                    <λ:C.K>
                                      CASE CHead c2 (Bind Void) (TSort O) OF
                                        CSort Bind Void
                                      | CHead  k0 k0
                                    <λ:C.K> CASE CHead c k v OF CSort Bind Void | CHead  k0 k0

                                  eq
                                    K
                                    λe:C.<λ:C.K> CASE e OF CSort Bind Void | CHead  k0 k0
                                      CHead c2 (Bind Void) (TSort O)
                                    λe:C.<λ:C.K> CASE e OF CSort Bind Void | CHead  k0 k0 (CHead c k v)
                            end of H6
                            (h1
                               (H7
                                  by (f_equal . . . . . H4)
                                  we proved 
                                     eq
                                       T
                                       <λ:C.T>
                                         CASE CHead c2 (Bind Void) (TSort O) OF
                                           CSort TSort O
                                         | CHead   tt
                                       <λ:C.T> CASE CHead c k v OF CSort TSort O | CHead   tt

                                     eq
                                       T
                                       λe:C.<λ:C.T> CASE e OF CSort TSort O | CHead   tt
                                         CHead c2 (Bind Void) (TSort O)
                                       λe:C.<λ:C.T> CASE e OF CSort TSort O | CHead   tt (CHead c k v)
                               end of H7
                                suppose H8eq K (Bind Void) k
                                suppose H9eq C c2 c
                                  (H10
                                     we proceed by induction on H9 to prove (eq C c (CHead c k v))(ex B λb0:B.eq K k (Bind b0))
                                        case refl_equal : 
                                           the thesis becomes the hypothesis H2
(eq C c (CHead c k v))(ex B λb0:B.eq K k (Bind b0))
                                  end of H10
                                  (H12
                                     by (eq_ind_r . . . H10 . H8)

                                        eq C c (CHead c (Bind Void) v)
                                          ex B λb0:B.eq K (Bind Void) (Bind b0)
                                  end of H12
                                  we proceed by induction on H8 to prove ex B λb0:B.eq K k (Bind b0)
                                     case refl_equal : 
                                        the thesis becomes ex B λb0:B.eq K (Bind Void) (Bind b0)
                                           by (refl_equal . .)
                                           we proved eq K (Bind Void) (Bind Void)
                                           by (ex_intro . . . previous)
ex B λb0:B.eq K (Bind Void) (Bind b0)
                                  we proved ex B λb0:B.eq K k (Bind b0)

                                  eq K (Bind Void) k
                                    (eq C c2 c)(ex B λb0:B.eq K k (Bind b0))
                            end of h1
                            (h2
                               consider H6
                               we proved 
                                  eq
                                    K
                                    <λ:C.K>
                                      CASE CHead c2 (Bind Void) (TSort O) OF
                                        CSort Bind Void
                                      | CHead  k0 k0
                                    <λ:C.K> CASE CHead c k v OF CSort Bind Void | CHead  k0 k0
eq K (Bind Void) k
                            end of h2
                            by (h1 h2)
(eq C c2 c)(ex B λb0:B.eq K k (Bind b0))
                         end of h1
                         (h2
                            consider H5
                            we proved 
                               eq
                                 C
                                 <λ:C.C> CASE CHead c2 (Bind Void) (TSort O) OF CSort c2 | CHead c0  c0
                                 <λ:C.C> CASE CHead c k v OF CSort c2 | CHead c0  c0
eq C c2 c
                         end of h2
                         by (h1 h2)
                         we proved ex B λb0:B.eq K k (Bind b0)

                         H4:eq C (CHead c2 (Bind Void) (TSort O)) (CHead c k v)
                           .ex B λb0:B.eq K k (Bind b0)
                case wf3_flat : c1:C c2:C H1:wf3 g c1 c2 :T :F 
                   the thesis becomes H3:(eq C c2 (CHead c k v)).(ex B λb:B.eq K k (Bind b))
                   (H2) by induction hypothesis we know (eq C c2 (CHead c k v))(ex B λb:B.eq K k (Bind b))
                      suppose H3eq C c2 (CHead c k v)
                         (H4
                            by (f_equal . . . . . H3)
                            we proved eq C c2 (CHead c k v)
eq C (λe:C.e c2) (λe:C.e (CHead c k v))
                         end of H4
                         (H5
                            we proceed by induction on H4 to prove 
                               eq C (CHead c k v) (CHead c k v)
                                 ex B λb:B.eq K k (Bind b)
                               case refl_equal : 
                                  the thesis becomes the hypothesis H2

                               eq C (CHead c k v) (CHead c k v)
                                 ex B λb:B.eq K k (Bind b)
                         end of H5
                         by (refl_equal . .)
                         we proved eq C (CHead c k v) (CHead c k v)
                         by (H5 previous)
                         we proved ex B λb:B.eq K k (Bind b)
H3:(eq C c2 (CHead c k v)).(ex B λb:B.eq K k (Bind b))
             we proved (eq C y (CHead c k v))(ex B λb:B.eq K k (Bind b))
          we proved 
             y:C
               .wf3 g x y
                 (eq C y (CHead c k v))(ex B λb:B.eq K k (Bind b))
          by (insert_eq . . . . previous H)
          we proved ex B λb:B.eq K k (Bind b)
       we proved g:G.x:C.c:C.v:T.k:K.(wf3 g x (CHead c k v))(ex B λb:B.eq K k (Bind b))