DEFINITION pr3_gen_abst()
TYPE =
       ∀c:C
         .∀u1:T
           .∀t1:T
             .∀x:T
               .pr3 c (THead (Bind Abst) u1 t1) x
                 →(ex3_2
                      T
                      T
                      λu2:T.λt2:T.eq T x (THead (Bind Abst) u2 t2)
                      λu2:T.λ:T.pr3 c u1 u2
                      λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) t1 t2))
BODY =
        assume c: C
        assume u1: T
        assume t1: T
        assume x: T
        suppose H: pr3 c (THead (Bind Abst) u1 t1) x
           assume y: T
           suppose H0: pr3 c y x
             we proceed by induction on H0 to prove 
                ∀x0:T
                  .∀x1:T
                    .eq T y (THead (Bind Abst) x0 x1)
                      →(ex3_2
                           T
                           T
                           λu2:T.λt2:T.eq T x (THead (Bind Abst) u2 t2)
                           λu2:T.λ:T.pr3 c x0 u2
                           λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t2))
                case pr3_refl : t:T ⇒
                   the thesis becomes 
                   ∀x0:T
                     .∀x1:T
                       .∀H1:eq T t (THead (Bind Abst) x0 x1)
                         .ex3_2
                           T
                           T
                           λu2:T.λt2:T.eq T t (THead (Bind Abst) u2 t2)
                           λu2:T.λ:T.pr3 c x0 u2
                           λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t2)
                       assume x0: T
                       assume x1: T
                       suppose H1: eq T t (THead (Bind Abst) x0 x1)
                         (h1) by (pr3_refl . .) we proved pr3 c x0 x0
                         (h2) 
                             assume b: B
                             assume u: T
                               by (pr3_refl . .)
                               we proved pr3 (CHead c (Bind b) u) x1 x1
∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 x1)
                         end of h2
                         by (ex3_2_intro . . . . . . . H1 h1 h2)
                         we proved 
                            ex3_2
                              T
                              T
                              λu2:T.λt2:T.eq T t (THead (Bind Abst) u2 t2)
                              λu2:T.λ:T.pr3 c x0 u2
                              λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t2)

                         ∀x0:T
                           .∀x1:T
                             .∀H1:eq T t (THead (Bind Abst) x0 x1)
                               .ex3_2
                                 T
                                 T
                                 λu2:T.λt2:T.eq T t (THead (Bind Abst) u2 t2)
                                 λu2:T.λ:T.pr3 c x0 u2
                                 λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t2)
                case pr3_sing : t2:T t3:T H1:pr2 c t3 t2 t4:T :pr3 c t2 t4 ⇒
                   the thesis becomes 
                   ∀x0:T
                     .∀x1:T
                       .∀H4:eq T t3 (THead (Bind Abst) x0 x1)
                         .ex3_2
                           T
                           T
                           λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                           λu2:T.λ:T.pr3 c x0 u2
                           λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)
                   (H3) by induction hypothesis we know 
                      ∀x0:T
                        .∀x1:T
                          .eq T t2 (THead (Bind Abst) x0 x1)
                            →(ex3_2
                                 T
                                 T
                                 λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                 λu2:T.λ:T.pr3 c x0 u2
                                 λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5))
                       assume x0: T
                       assume x1: T
                       suppose H4: eq T t3 (THead (Bind Abst) x0 x1)
                         (H5) 
                            we proceed by induction on H4 to prove pr2 c (THead (Bind Abst) x0 x1) t2
                               case refl_equal : ⇒
                                  the thesis becomes the hypothesis H1
pr2 c (THead (Bind Abst) x0 x1) t2
                         end of H5
                         (H6) 
                            by (pr2_gen_abst . . . . H5)

                               ex3_2
                                 T
                                 T
                                 λu2:T.λt2:T.eq T t2 (THead (Bind Abst) u2 t2)
                                 λu2:T.λ:T.pr2 c x0 u2
                                 λ:T.λt2:T.∀b:B.∀u:T.(pr2 (CHead c (Bind b) u) x1 t2)
                         end of H6
                         we proceed by induction on H6 to prove 
                            ex3_2
                              T
                              T
                              λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                              λu2:T.λ:T.pr3 c x0 u2
                              λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)
                            case ex3_2_intro : x2:T x3:T H7:eq T t2 (THead (Bind Abst) x2 x3) H8:pr2 c x0 x2 H9:∀b:B.∀u:T.(pr2 (CHead c (Bind b) u) x1 x3) ⇒
                               the thesis becomes 
                               ex3_2
                                 T
                                 T
                                 λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                 λu2:T.λ:T.pr3 c x0 u2
                                 λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)
                                  (H10) 
                                     we proceed by induction on H7 to prove 
                                        ∀x4:T
                                          .∀x5:T
                                            .eq T (THead (Bind Abst) x2 x3) (THead (Bind Abst) x4 x5)
                                              →(ex3_2
                                                   T
                                                   T
                                                   λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                                   λu2:T.λ:T.pr3 c x4 u2
                                                   λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x5 t5))
                                        case refl_equal : ⇒
                                           the thesis becomes the hypothesis H3

                                        ∀x4:T
                                          .∀x5:T
                                            .eq T (THead (Bind Abst) x2 x3) (THead (Bind Abst) x4 x5)
                                              →(ex3_2
                                                   T
                                                   T
                                                   λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                                   λu2:T.λ:T.pr3 c x4 u2
                                                   λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x5 t5))
                                  end of H10
                                  (H11) 
                                     by (refl_equal . .)
                                     we proved eq T (THead (Bind Abst) x2 x3) (THead (Bind Abst) x2 x3)
                                     by (H10 . . previous)

                                        ex3_2
                                          T
                                          T
                                          λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                          λu2:T.λ:T.pr3 c x2 u2
                                          λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x3 t5)
                                  end of H11
                                  we proceed by induction on H11 to prove 
                                     ex3_2
                                       T
                                       T
                                       λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                       λu2:T.λ:T.pr3 c x0 u2
                                       λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)
                                     case ex3_2_intro : x4:T x5:T H12:eq T t4 (THead (Bind Abst) x4 x5) H13:pr3 c x2 x4 H14:∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x3 x5) ⇒
                                        the thesis becomes 
                                        ex3_2
                                          T
                                          T
                                          λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                          λu2:T.λ:T.pr3 c x0 u2
                                          λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)
                                           (h1) 
                                              by (pr3_sing . . . H8 . H13)
pr3 c x0 x4
                                           end of h1
                                           (h2) 
                                               assume b: B
                                               assume u: T
                                                 (h1) 
                                                    by (H9 . .)
pr2 (CHead c (Bind b) u) x1 x3
                                                 end of h1
                                                 (h2) 
                                                    by (H14 . .)
pr3 (CHead c (Bind b) u) x3 x5
                                                 end of h2
                                                 by (pr3_sing . . . h1 . h2)
                                                 we proved pr3 (CHead c (Bind b) u) x1 x5
∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 x5)
                                           end of h2
                                           by (ex3_2_intro . . . . . . . H12 h1 h2)

                                              ex3_2
                                                T
                                                T
                                                λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                                λu2:T.λ:T.pr3 c x0 u2
                                                λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)

                                     ex3_2
                                       T
                                       T
                                       λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                       λu2:T.λ:T.pr3 c x0 u2
                                       λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)
                         we proved 
                            ex3_2
                              T
                              T
                              λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                              λu2:T.λ:T.pr3 c x0 u2
                              λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)

                         ∀x0:T
                           .∀x1:T
                             .∀H4:eq T t3 (THead (Bind Abst) x0 x1)
                               .ex3_2
                                 T
                                 T
                                 λu2:T.λt5:T.eq T t4 (THead (Bind Abst) u2 t5)
                                 λu2:T.λ:T.pr3 c x0 u2
                                 λ:T.λt5:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t5)
             we proved 
                ∀x0:T
                  .∀x1:T
                    .eq T y (THead (Bind Abst) x0 x1)
                      →(ex3_2
                           T
                           T
                           λu2:T.λt2:T.eq T x (THead (Bind Abst) u2 t2)
                           λu2:T.λ:T.pr3 c x0 u2
                           λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x1 t2))
             by (unintro . . . previous)
             we proved 
                ∀x0:T
                  .eq T y (THead (Bind Abst) u1 x0)
                    →(ex3_2
                         T
                         T
                         λu2:T.λt2:T.eq T x (THead (Bind Abst) u2 t2)
                         λu2:T.λ:T.pr3 c u1 u2
                         λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) x0 t2))
             by (unintro . . . previous)
             we proved 
                eq T y (THead (Bind Abst) u1 t1)
                  →(ex3_2
                       T
                       T
                       λu2:T.λt2:T.eq T x (THead (Bind Abst) u2 t2)
                       λu2:T.λ:T.pr3 c u1 u2
                       λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) t1 t2))
          we proved 
             ∀y:T
               .pr3 c y x
                 →(eq T y (THead (Bind Abst) u1 t1)
                      →(ex3_2
                           T
                           T
                           λu2:T.λt2:T.eq T x (THead (Bind Abst) u2 t2)
                           λu2:T.λ:T.pr3 c u1 u2
                           λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) t1 t2)))
          by (insert_eq . . . . previous H)
          we proved 
             ex3_2
               T
               T
               λu2:T.λt2:T.eq T x (THead (Bind Abst) u2 t2)
               λu2:T.λ:T.pr3 c u1 u2
               λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) t1 t2)
       we proved 
          ∀c:C
            .∀u1:T
              .∀t1:T
                .∀x:T
                  .pr3 c (THead (Bind Abst) u1 t1) x
                    →(ex3_2
                         T
                         T
                         λu2:T.λt2:T.eq T x (THead (Bind Abst) u2 t2)
                         λu2:T.λ:T.pr3 c u1 u2
                         λ:T.λt2:T.∀b:B.∀u:T.(pr3 (CHead c (Bind b) u) t1 t2))