DEFINITION wf3_gen_bind1()
TYPE =
       g:G
         .c1:C
           .x:C
             .v:T
               .b:B
                 .wf3 g (CHead c1 (Bind b) v) x
                   (or
                        ex3_2 C T λc2:C.λ:T.eq C x (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                        ex3
                          C
                          λc2:C.eq C x (CHead c2 (Bind Void) (TSort O))
                          λc2:C.wf3 g c1 c2
                          λ:C.w:T.(ty3 g c1 v w)False)
BODY =
        assume gG
        assume c1C
        assume xC
        assume vT
        assume bB
        suppose Hwf3 g (CHead c1 (Bind b) v) x
           assume yC
           suppose H0wf3 g y x
             we proceed by induction on H0 to prove 
                eq C y (CHead c1 (Bind b) v)
                  (or
                       ex3_2 C T λc2:C.λ:T.eq C x (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                       ex3
                         C
                         λc2:C.eq C x (CHead c2 (Bind Void) (TSort O))
                         λc2:C.wf3 g c1 c2
                         λ:C.w:T.(ty3 g c1 v w)False)
                case wf3_sort : m:nat 
                   the thesis becomes 
                   H1:eq C (CSort m) (CHead c1 (Bind b) v)
                     .or
                       ex3_2 C T λc2:C.λ:T.eq C (CSort m) (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                       ex3
                         C
                         λc2:C.eq C (CSort m) (CHead c2 (Bind Void) (TSort O))
                         λc2:C.wf3 g c1 c2
                         λ:C.w:T.(ty3 g c1 v w)False
                      suppose H1eq C (CSort m) (CHead c1 (Bind b) v)
                         (H2
                            we proceed by induction on H1 to prove <λ:C.Prop> CASE CHead c1 (Bind b) 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 c1 (Bind b) v OF CSort True | CHead   False
                         end of H2
                         consider H2
                         we proved <λ:C.Prop> CASE CHead c1 (Bind b) v OF CSort True | CHead   False
                         that is equivalent to False
                         we proceed by induction on the previous result to prove 
                            or
                              ex3_2 C T λc2:C.λ:T.eq C (CSort m) (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                              ex3
                                C
                                λc2:C.eq C (CSort m) (CHead c2 (Bind Void) (TSort O))
                                λc2:C.wf3 g c1 c2
                                λ:C.w:T.(ty3 g c1 v w)False
                         we proved 
                            or
                              ex3_2 C T λc2:C.λ:T.eq C (CSort m) (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                              ex3
                                C
                                λc2:C.eq C (CSort m) (CHead c2 (Bind Void) (TSort O))
                                λc2:C.wf3 g c1 c2
                                λ:C.w:T.(ty3 g c1 v w)False

                         H1:eq C (CSort m) (CHead c1 (Bind b) v)
                           .or
                             ex3_2 C T λc2:C.λ:T.eq C (CSort m) (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                             ex3
                               C
                               λc2:C.eq C (CSort m) (CHead c2 (Bind Void) (TSort O))
                               λc2:C.wf3 g c1 c2
                               λ:C.w:T.(ty3 g c1 v w)False
                case wf3_bind : c0:C c2:C H1:wf3 g c0 c2 u:T t:T H3:ty3 g c0 u t b0:B 
                   the thesis becomes 
                   H4:eq C (CHead c0 (Bind b0) u) (CHead c1 (Bind b) v)
                     .or
                       ex3_2
                         C
                         T
                         λc3:C.λ:T.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind b) v)
                         λc3:C.λ:T.wf3 g c1 c3
                         λ:C.λw:T.ty3 g c1 v w
                       ex3
                         C
                         λc3:C.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind Void) (TSort O))
                         λc3:C.wf3 g c1 c3
                         λ:C.w:T.(ty3 g c1 v w)False
                   (H2) by induction hypothesis we know 
                      eq C c0 (CHead c1 (Bind b) v)
                        (or
                             ex3_2 C T λc3:C.λ:T.eq C c2 (CHead c3 (Bind b) v) λc3:C.λ:T.wf3 g c1 c3 λ:C.λw:T.ty3 g c1 v w
                             ex3
                               C
                               λc3:C.eq C c2 (CHead c3 (Bind Void) (TSort O))
                               λc3:C.wf3 g c1 c3
                               λ:C.w:T.(ty3 g c1 v w)False)
                      suppose H4eq C (CHead c0 (Bind b0) u) (CHead c1 (Bind b) v)
                         (H5
                            by (f_equal . . . . . H4)
                            we proved 
                               eq
                                 C
                                 <λ:C.C> CASE CHead c0 (Bind b0) u OF CSort c0 | CHead c  c
                                 <λ:C.C> CASE CHead c1 (Bind b) v OF CSort c0 | CHead c  c

                               eq
                                 C
                                 λe:C.<λ:C.C> CASE e OF CSort c0 | CHead c  c (CHead c0 (Bind b0) u)
                                 λe:C.<λ:C.C> CASE e OF CSort c0 | CHead c  c (CHead c1 (Bind b) v)
                         end of H5
                         (h1
                            (H6
                               by (f_equal . . . . . H4)
                               we proved 
                                  eq
                                    B
                                    <λ:C.B>
                                      CASE CHead c0 (Bind b0) u OF
                                        CSort b0
                                      | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
                                    <λ:C.B>
                                      CASE CHead c1 (Bind b) v OF
                                        CSort b0
                                      | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0

                                  eq
                                    B
                                    λe:C.<λ:C.B> CASE e OF CSort b0 | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
                                      CHead c0 (Bind b0) u
                                    λe:C.<λ:C.B> CASE e OF CSort b0 | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
                                      CHead c1 (Bind b) v
                            end of H6
                            (h1
                               (H7
                                  by (f_equal . . . . . H4)
                                  we proved 
                                     eq
                                       T
                                       <λ:C.T> CASE CHead c0 (Bind b0) u OF CSort u | CHead   t0t0
                                       <λ:C.T> CASE CHead c1 (Bind b) v OF CSort u | CHead   t0t0

                                     eq
                                       T
                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   t0t0 (CHead c0 (Bind b0) u)
                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   t0t0 (CHead c1 (Bind b) v)
                               end of H7
                                suppose H8eq B b0 b
                                suppose H9eq C c0 c1
                                  (H10
                                     consider H7
                                     we proved 
                                        eq
                                          T
                                          <λ:C.T> CASE CHead c0 (Bind b0) u OF CSort u | CHead   t0t0
                                          <λ:C.T> CASE CHead c1 (Bind b) v OF CSort u | CHead   t0t0
                                     that is equivalent to eq T u v
                                     we proceed by induction on the previous result to prove ty3 g c0 v t
                                        case refl_equal : 
                                           the thesis becomes the hypothesis H3
ty3 g c0 v t
                                  end of H10
                                  (h1
                                     (H11
                                        we proceed by induction on H9 to prove ty3 g c1 v t
                                           case refl_equal : 
                                              the thesis becomes the hypothesis H10
ty3 g c1 v t
                                     end of H11
                                     (H13
                                        we proceed by induction on H9 to prove wf3 g c1 c2
                                           case refl_equal : 
                                              the thesis becomes the hypothesis H1
wf3 g c1 c2
                                     end of H13
                                     by (refl_equal . .)
                                     we proved eq C (CHead c2 (Bind b) v) (CHead c2 (Bind b) v)
                                     by (ex3_2_intro . . . . . . . previous H13 H11)
                                     we proved 
                                        ex3_2
                                          C
                                          T
                                          λc3:C.λ:T.eq C (CHead c2 (Bind b) v) (CHead c3 (Bind b) v)
                                          λc3:C.λ:T.wf3 g c1 c3
                                          λ:C.λw:T.ty3 g c1 v w
                                     by (or_introl . . previous)

                                        or
                                          ex3_2
                                            C
                                            T
                                            λc3:C.λ:T.eq C (CHead c2 (Bind b) v) (CHead c3 (Bind b) v)
                                            λc3:C.λ:T.wf3 g c1 c3
                                            λ:C.λw:T.ty3 g c1 v w
                                          ex3
                                            C
                                            λc3:C.eq C (CHead c2 (Bind b) v) (CHead c3 (Bind Void) (TSort O))
                                            λc3:C.wf3 g c1 c3
                                            λ:C.w:T.(ty3 g c1 v w)False
                                  end of h1
                                  (h2
                                     consider H7
                                     we proved 
                                        eq
                                          T
                                          <λ:C.T> CASE CHead c0 (Bind b0) u OF CSort u | CHead   t0t0
                                          <λ:C.T> CASE CHead c1 (Bind b) v OF CSort u | CHead   t0t0
eq T u v
                                  end of h2
                                  by (eq_ind_r . . . h1 . h2)
                                  we proved 
                                     or
                                       ex3_2
                                         C
                                         T
                                         λc3:C.λ:T.eq C (CHead c2 (Bind b) u) (CHead c3 (Bind b) v)
                                         λc3:C.λ:T.wf3 g c1 c3
                                         λ:C.λw:T.ty3 g c1 v w
                                       ex3
                                         C
                                         λc3:C.eq C (CHead c2 (Bind b) u) (CHead c3 (Bind Void) (TSort O))
                                         λc3:C.wf3 g c1 c3
                                         λ:C.w:T.(ty3 g c1 v w)False
                                  by (eq_ind_r . . . previous . H8)
                                  we proved 
                                     or
                                       ex3_2
                                         C
                                         T
                                         λc3:C.λ:T.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind b) v)
                                         λc3:C.λ:T.wf3 g c1 c3
                                         λ:C.λw:T.ty3 g c1 v w
                                       ex3
                                         C
                                         λc3:C.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind Void) (TSort O))
                                         λc3:C.wf3 g c1 c3
                                         λ:C.w:T.(ty3 g c1 v w)False

                                  eq B b0 b
                                    (eq C c0 c1
                                         (or
                                              ex3_2
                                                C
                                                T
                                                λc3:C.λ:T.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind b) v)
                                                λc3:C.λ:T.wf3 g c1 c3
                                                λ:C.λw:T.ty3 g c1 v w
                                              ex3
                                                C
                                                λc3:C.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind Void) (TSort O))
                                                λc3:C.wf3 g c1 c3
                                                λ:C.w:T.(ty3 g c1 v w)False))
                            end of h1
                            (h2
                               consider H6
                               we proved 
                                  eq
                                    B
                                    <λ:C.B>
                                      CASE CHead c0 (Bind b0) u OF
                                        CSort b0
                                      | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
                                    <λ:C.B>
                                      CASE CHead c1 (Bind b) v OF
                                        CSort b0
                                      | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
eq B b0 b
                            end of h2
                            by (h1 h2)

                               eq C c0 c1
                                 (or
                                      ex3_2
                                        C
                                        T
                                        λc3:C.λ:T.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind b) v)
                                        λc3:C.λ:T.wf3 g c1 c3
                                        λ:C.λw:T.ty3 g c1 v w
                                      ex3
                                        C
                                        λc3:C.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind Void) (TSort O))
                                        λc3:C.wf3 g c1 c3
                                        λ:C.w:T.(ty3 g c1 v w)False)
                         end of h1
                         (h2
                            consider H5
                            we proved 
                               eq
                                 C
                                 <λ:C.C> CASE CHead c0 (Bind b0) u OF CSort c0 | CHead c  c
                                 <λ:C.C> CASE CHead c1 (Bind b) v OF CSort c0 | CHead c  c
eq C c0 c1
                         end of h2
                         by (h1 h2)
                         we proved 
                            or
                              ex3_2
                                C
                                T
                                λc3:C.λ:T.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind b) v)
                                λc3:C.λ:T.wf3 g c1 c3
                                λ:C.λw:T.ty3 g c1 v w
                              ex3
                                C
                                λc3:C.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind Void) (TSort O))
                                λc3:C.wf3 g c1 c3
                                λ:C.w:T.(ty3 g c1 v w)False

                         H4:eq C (CHead c0 (Bind b0) u) (CHead c1 (Bind b) v)
                           .or
                             ex3_2
                               C
                               T
                               λc3:C.λ:T.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind b) v)
                               λc3:C.λ:T.wf3 g c1 c3
                               λ:C.λw:T.ty3 g c1 v w
                             ex3
                               C
                               λc3:C.eq C (CHead c2 (Bind b0) u) (CHead c3 (Bind Void) (TSort O))
                               λc3:C.wf3 g c1 c3
                               λ:C.w:T.(ty3 g c1 v w)False
                case wf3_void : c0:C c2:C H1:wf3 g c0 c2 u:T H3:t:T.(ty3 g c0 u t)False b0:B 
                   the thesis becomes 
                   H4:eq C (CHead c0 (Bind b0) u) (CHead c1 (Bind b) v)
                     .or
                       ex3_2
                         C
                         T
                         λc3:C.λ:T.eq C (CHead c2 (Bind Void) (TSort O)) (CHead c3 (Bind b) v)
                         λc3:C.λ:T.wf3 g c1 c3
                         λ:C.λw:T.ty3 g c1 v w
                       ex3
                         C
                         λc3:C
                           .eq
                             C
                             CHead c2 (Bind Void) (TSort O)
                             CHead c3 (Bind Void) (TSort O)
                         λc3:C.wf3 g c1 c3
                         λ:C.w:T.(ty3 g c1 v w)False
                   (H2) by induction hypothesis we know 
                      eq C c0 (CHead c1 (Bind b) v)
                        (or
                             ex3_2 C T λc3:C.λ:T.eq C c2 (CHead c3 (Bind b) v) λc3:C.λ:T.wf3 g c1 c3 λ:C.λw:T.ty3 g c1 v w
                             ex3
                               C
                               λc3:C.eq C c2 (CHead c3 (Bind Void) (TSort O))
                               λc3:C.wf3 g c1 c3
                               λ:C.w:T.(ty3 g c1 v w)False)
                      suppose H4eq C (CHead c0 (Bind b0) u) (CHead c1 (Bind b) v)
                         (H5
                            by (f_equal . . . . . H4)
                            we proved 
                               eq
                                 C
                                 <λ:C.C> CASE CHead c0 (Bind b0) u OF CSort c0 | CHead c  c
                                 <λ:C.C> CASE CHead c1 (Bind b) v OF CSort c0 | CHead c  c

                               eq
                                 C
                                 λe:C.<λ:C.C> CASE e OF CSort c0 | CHead c  c (CHead c0 (Bind b0) u)
                                 λe:C.<λ:C.C> CASE e OF CSort c0 | CHead c  c (CHead c1 (Bind b) v)
                         end of H5
                         (h1
                            (H6
                               by (f_equal . . . . . H4)
                               we proved 
                                  eq
                                    B
                                    <λ:C.B>
                                      CASE CHead c0 (Bind b0) u OF
                                        CSort b0
                                      | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
                                    <λ:C.B>
                                      CASE CHead c1 (Bind b) v OF
                                        CSort b0
                                      | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0

                                  eq
                                    B
                                    λe:C.<λ:C.B> CASE e OF CSort b0 | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
                                      CHead c0 (Bind b0) u
                                    λe:C.<λ:C.B> CASE e OF CSort b0 | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
                                      CHead c1 (Bind b) v
                            end of H6
                            (h1
                               (H7
                                  by (f_equal . . . . . H4)
                                  we proved 
                                     eq
                                       T
                                       <λ:C.T> CASE CHead c0 (Bind b0) u OF CSort u | CHead   tt
                                       <λ:C.T> CASE CHead c1 (Bind b) v OF CSort u | CHead   tt

                                     eq
                                       T
                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead c0 (Bind b0) u)
                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead c1 (Bind b) v)
                               end of H7
                                suppose eq B b0 b
                                suppose H9eq C c0 c1
                                  (H10
                                     consider H7
                                     we proved 
                                        eq
                                          T
                                          <λ:C.T> CASE CHead c0 (Bind b0) u OF CSort u | CHead   tt
                                          <λ:C.T> CASE CHead c1 (Bind b) v OF CSort u | CHead   tt
                                     that is equivalent to eq T u v
                                     we proceed by induction on the previous result to prove t0:T.(ty3 g c0 v t0)False
                                        case refl_equal : 
                                           the thesis becomes the hypothesis H3
t0:T.(ty3 g c0 v t0)False
                                  end of H10
                                  (H11
                                     we proceed by induction on H9 to prove t:T.(ty3 g c1 v t)False
                                        case refl_equal : 
                                           the thesis becomes the hypothesis H10
t:T.(ty3 g c1 v t)False
                                  end of H11
                                  (H13
                                     we proceed by induction on H9 to prove wf3 g c1 c2
                                        case refl_equal : 
                                           the thesis becomes the hypothesis H1
wf3 g c1 c2
                                  end of H13
                                  by (refl_equal . .)
                                  we proved 
                                     eq
                                       C
                                       CHead c2 (Bind Void) (TSort O)
                                       CHead c2 (Bind Void) (TSort O)
                                  by (ex3_intro . . . . . previous H13 H11)
                                  we proved 
                                     ex3
                                       C
                                       λc3:C
                                         .eq
                                           C
                                           CHead c2 (Bind Void) (TSort O)
                                           CHead c3 (Bind Void) (TSort O)
                                       λc3:C.wf3 g c1 c3
                                       λ:C.w:T.(ty3 g c1 v w)False
                                  by (or_intror . . previous)
                                  we proved 
                                     or
                                       ex3_2
                                         C
                                         T
                                         λc3:C.λ:T.eq C (CHead c2 (Bind Void) (TSort O)) (CHead c3 (Bind b) v)
                                         λc3:C.λ:T.wf3 g c1 c3
                                         λ:C.λw:T.ty3 g c1 v w
                                       ex3
                                         C
                                         λc3:C
                                           .eq
                                             C
                                             CHead c2 (Bind Void) (TSort O)
                                             CHead c3 (Bind Void) (TSort O)
                                         λc3:C.wf3 g c1 c3
                                         λ:C.w:T.(ty3 g c1 v w)False

                                  eq B b0 b
                                    (eq C c0 c1
                                         (or
                                              ex3_2
                                                C
                                                T
                                                λc3:C.λ:T.eq C (CHead c2 (Bind Void) (TSort O)) (CHead c3 (Bind b) v)
                                                λc3:C.λ:T.wf3 g c1 c3
                                                λ:C.λw:T.ty3 g c1 v w
                                              ex3
                                                C
                                                λc3:C
                                                  .eq
                                                    C
                                                    CHead c2 (Bind Void) (TSort O)
                                                    CHead c3 (Bind Void) (TSort O)
                                                λc3:C.wf3 g c1 c3
                                                λ:C.w:T.(ty3 g c1 v w)False))
                            end of h1
                            (h2
                               consider H6
                               we proved 
                                  eq
                                    B
                                    <λ:C.B>
                                      CASE CHead c0 (Bind b0) u OF
                                        CSort b0
                                      | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
                                    <λ:C.B>
                                      CASE CHead c1 (Bind b) v OF
                                        CSort b0
                                      | CHead  k <λ:K.B> CASE k OF Bind b1b1 | Flat b0
eq B b0 b
                            end of h2
                            by (h1 h2)

                               eq C c0 c1
                                 (or
                                      ex3_2
                                        C
                                        T
                                        λc3:C.λ:T.eq C (CHead c2 (Bind Void) (TSort O)) (CHead c3 (Bind b) v)
                                        λc3:C.λ:T.wf3 g c1 c3
                                        λ:C.λw:T.ty3 g c1 v w
                                      ex3
                                        C
                                        λc3:C
                                          .eq
                                            C
                                            CHead c2 (Bind Void) (TSort O)
                                            CHead c3 (Bind Void) (TSort O)
                                        λc3:C.wf3 g c1 c3
                                        λ:C.w:T.(ty3 g c1 v w)False)
                         end of h1
                         (h2
                            consider H5
                            we proved 
                               eq
                                 C
                                 <λ:C.C> CASE CHead c0 (Bind b0) u OF CSort c0 | CHead c  c
                                 <λ:C.C> CASE CHead c1 (Bind b) v OF CSort c0 | CHead c  c
eq C c0 c1
                         end of h2
                         by (h1 h2)
                         we proved 
                            or
                              ex3_2
                                C
                                T
                                λc3:C.λ:T.eq C (CHead c2 (Bind Void) (TSort O)) (CHead c3 (Bind b) v)
                                λc3:C.λ:T.wf3 g c1 c3
                                λ:C.λw:T.ty3 g c1 v w
                              ex3
                                C
                                λc3:C
                                  .eq
                                    C
                                    CHead c2 (Bind Void) (TSort O)
                                    CHead c3 (Bind Void) (TSort O)
                                λc3:C.wf3 g c1 c3
                                λ:C.w:T.(ty3 g c1 v w)False

                         H4:eq C (CHead c0 (Bind b0) u) (CHead c1 (Bind b) v)
                           .or
                             ex3_2
                               C
                               T
                               λc3:C.λ:T.eq C (CHead c2 (Bind Void) (TSort O)) (CHead c3 (Bind b) v)
                               λc3:C.λ:T.wf3 g c1 c3
                               λ:C.λw:T.ty3 g c1 v w
                             ex3
                               C
                               λc3:C
                                 .eq
                                   C
                                   CHead c2 (Bind Void) (TSort O)
                                   CHead c3 (Bind Void) (TSort O)
                               λc3:C.wf3 g c1 c3
                               λ:C.w:T.(ty3 g c1 v w)False
                case wf3_flat : c0:C c2:C :wf3 g c0 c2 u:T f:F 
                   the thesis becomes 
                   H3:eq C (CHead c0 (Flat f) u) (CHead c1 (Bind b) v)
                     .or
                       ex3_2 C T λc3:C.λ:T.eq C c2 (CHead c3 (Bind b) v) λc3:C.λ:T.wf3 g c1 c3 λ:C.λw:T.ty3 g c1 v w
                       ex3
                         C
                         λc3:C.eq C c2 (CHead c3 (Bind Void) (TSort O))
                         λc3:C.wf3 g c1 c3
                         λ:C.w:T.(ty3 g c1 v w)False
                   () by induction hypothesis we know 
                      eq C c0 (CHead c1 (Bind b) v)
                        (or
                             ex3_2 C T λc3:C.λ:T.eq C c2 (CHead c3 (Bind b) v) λc3:C.λ:T.wf3 g c1 c3 λ:C.λw:T.ty3 g c1 v w
                             ex3
                               C
                               λc3:C.eq C c2 (CHead c3 (Bind Void) (TSort O))
                               λc3:C.wf3 g c1 c3
                               λ:C.w:T.(ty3 g c1 v w)False)
                      suppose H3eq C (CHead c0 (Flat f) u) (CHead c1 (Bind b) v)
                         (H4
                            we proceed by induction on H3 to prove 
                               <λ:C.Prop>
                                 CASE CHead c1 (Bind b) v OF
                                   CSort False
                                 | CHead  k <λ:K.Prop> CASE k OF Bind False | Flat True
                               case refl_equal : 
                                  the thesis becomes 
                                  <λ:C.Prop>
                                    CASE CHead c0 (Flat f) u OF
                                      CSort False
                                    | CHead  k <λ:K.Prop> CASE k OF Bind False | Flat True
                                     consider I
                                     we proved True

                                        <λ:C.Prop>
                                          CASE CHead c0 (Flat f) u OF
                                            CSort False
                                          | CHead  k <λ:K.Prop> CASE k OF Bind False | Flat True

                               <λ:C.Prop>
                                 CASE CHead c1 (Bind b) v OF
                                   CSort False
                                 | CHead  k <λ:K.Prop> CASE k OF Bind False | Flat True
                         end of H4
                         consider H4
                         we proved 
                            <λ:C.Prop>
                              CASE CHead c1 (Bind b) v OF
                                CSort False
                              | CHead  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 
                            or
                              ex3_2 C T λc3:C.λ:T.eq C c2 (CHead c3 (Bind b) v) λc3:C.λ:T.wf3 g c1 c3 λ:C.λw:T.ty3 g c1 v w
                              ex3
                                C
                                λc3:C.eq C c2 (CHead c3 (Bind Void) (TSort O))
                                λc3:C.wf3 g c1 c3
                                λ:C.w:T.(ty3 g c1 v w)False
                         we proved 
                            or
                              ex3_2 C T λc3:C.λ:T.eq C c2 (CHead c3 (Bind b) v) λc3:C.λ:T.wf3 g c1 c3 λ:C.λw:T.ty3 g c1 v w
                              ex3
                                C
                                λc3:C.eq C c2 (CHead c3 (Bind Void) (TSort O))
                                λc3:C.wf3 g c1 c3
                                λ:C.w:T.(ty3 g c1 v w)False

                         H3:eq C (CHead c0 (Flat f) u) (CHead c1 (Bind b) v)
                           .or
                             ex3_2 C T λc3:C.λ:T.eq C c2 (CHead c3 (Bind b) v) λc3:C.λ:T.wf3 g c1 c3 λ:C.λw:T.ty3 g c1 v w
                             ex3
                               C
                               λc3:C.eq C c2 (CHead c3 (Bind Void) (TSort O))
                               λc3:C.wf3 g c1 c3
                               λ:C.w:T.(ty3 g c1 v w)False
             we proved 
                eq C y (CHead c1 (Bind b) v)
                  (or
                       ex3_2 C T λc2:C.λ:T.eq C x (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                       ex3
                         C
                         λc2:C.eq C x (CHead c2 (Bind Void) (TSort O))
                         λc2:C.wf3 g c1 c2
                         λ:C.w:T.(ty3 g c1 v w)False)
          we proved 
             y:C
               .wf3 g y x
                 (eq C y (CHead c1 (Bind b) v)
                      (or
                           ex3_2 C T λc2:C.λ:T.eq C x (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                           ex3
                             C
                             λc2:C.eq C x (CHead c2 (Bind Void) (TSort O))
                             λc2:C.wf3 g c1 c2
                             λ:C.w:T.(ty3 g c1 v w)False))
          by (insert_eq . . . . previous H)
          we proved 
             or
               ex3_2 C T λc2:C.λ:T.eq C x (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
               ex3
                 C
                 λc2:C.eq C x (CHead c2 (Bind Void) (TSort O))
                 λc2:C.wf3 g c1 c2
                 λ:C.w:T.(ty3 g c1 v w)False
       we proved 
          g:G
            .c1:C
              .x:C
                .v:T
                  .b:B
                    .wf3 g (CHead c1 (Bind b) v) x
                      (or
                           ex3_2 C T λc2:C.λ:T.eq C x (CHead c2 (Bind b) v) λc2:C.λ:T.wf3 g c1 c2 λ:C.λw:T.ty3 g c1 v w
                           ex3
                             C
                             λc2:C.eq C x (CHead c2 (Bind Void) (TSort O))
                             λc2:C.wf3 g c1 c2
                             λ:C.w:T.(ty3 g c1 v w)False)