DEFINITION arity_fsubst0()
TYPE =
       g:G
         .c1:C
           .t1:T
             .a:A
               .arity g c1 t1 a
                 d1:C
                      .u:T
                        .i:nat
                          .(getl i c1 (CHead d1 (Bind Abbr) u))c2:C.t2:T.(fsubst0 i u c1 t1 c2 t2)(arity g c2 t2 a)
BODY =
        assume gG
        assume c1C
        assume t1T
        assume aA
        suppose Harity g c1 t1 a
          we proceed by induction on H to prove 
             d1:C
               .u:T
                 .i:nat
                   .(getl i c1 (CHead d1 (Bind Abbr) u))c2:C.t2:T.(fsubst0 i u c1 t1 c2 t2)(arity g c2 t2 a)
             case arity_sort : c:C n:nat 
                the thesis becomes 
                d1:C
                  .u:T
                    .i:nat
                      .getl i c (CHead d1 (Bind Abbr) u)
                        c2:C.t2:T.H1:(fsubst0 i u c (TSort n) c2 t2).(arity g c2 t2 (ASort O n))
                    assume d1C
                    assume uT
                    assume inat
                    suppose getl i c (CHead d1 (Bind Abbr) u)
                    assume c2C
                    assume t2T
                    suppose H1fsubst0 i u c (TSort n) c2 t2
                      (H_x
                         by (fsubst0_gen_base . . . . . . H1)

                            or3
                              land (eq C c c2) (subst0 i u (TSort n) t2)
                              land (eq T (TSort n) t2) (csubst0 i u c c2)
                              land (subst0 i u (TSort n) t2) (csubst0 i u c c2)
                      end of H_x
                      (H2consider H_x
                      we proceed by induction on H2 to prove arity g c2 t2 (ASort O n)
                         case or3_intro0 : H3:land (eq C c c2) (subst0 i u (TSort n) t2) 
                            the thesis becomes arity g c2 t2 (ASort O n)
                               we proceed by induction on H3 to prove arity g c2 t2 (ASort O n)
                                  case conj : H4:eq C c c2 H5:subst0 i u (TSort n) t2 
                                     the thesis becomes arity g c2 t2 (ASort O n)
                                        we proceed by induction on H4 to prove arity g c2 t2 (ASort O n)
                                           case refl_equal : 
                                              the thesis becomes arity g c t2 (ASort O n)
                                                 by (subst0_gen_sort . . . . H5 .)
arity g c t2 (ASort O n)
arity g c2 t2 (ASort O n)
arity g c2 t2 (ASort O n)
                         case or3_intro1 : H3:land (eq T (TSort n) t2) (csubst0 i u c c2) 
                            the thesis becomes arity g c2 t2 (ASort O n)
                               we proceed by induction on H3 to prove arity g c2 t2 (ASort O n)
                                  case conj : H4:eq T (TSort n) t2 :csubst0 i u c c2 
                                     the thesis becomes arity g c2 t2 (ASort O n)
                                        we proceed by induction on H4 to prove arity g c2 t2 (ASort O n)
                                           case refl_equal : 
                                              the thesis becomes arity g c2 (TSort n) (ASort O n)
                                                 by (arity_sort . . .)
arity g c2 (TSort n) (ASort O n)
arity g c2 t2 (ASort O n)
arity g c2 t2 (ASort O n)
                         case or3_intro2 : H3:land (subst0 i u (TSort n) t2) (csubst0 i u c c2) 
                            the thesis becomes arity g c2 t2 (ASort O n)
                               we proceed by induction on H3 to prove arity g c2 t2 (ASort O n)
                                  case conj : H4:subst0 i u (TSort n) t2 :csubst0 i u c c2 
                                     the thesis becomes arity g c2 t2 (ASort O n)
                                        by (subst0_gen_sort . . . . H4 .)
arity g c2 t2 (ASort O n)
arity g c2 t2 (ASort O n)
                      we proved arity g c2 t2 (ASort O n)

                      d1:C
                        .u:T
                          .i:nat
                            .getl i c (CHead d1 (Bind Abbr) u)
                              c2:C.t2:T.H1:(fsubst0 i u c (TSort n) c2 t2).(arity g c2 t2 (ASort O n))
             case arity_abbr : c:C d:C u:T i:nat H0:getl i c (CHead d (Bind Abbr) u) a0:A H1:arity g d u a0 
                the thesis becomes 
                d1:C
                  .u0:T.i0:nat.H3:(getl i0 c (CHead d1 (Bind Abbr) u0)).c2:C.t2:T.H4:(fsubst0 i0 u0 c (TLRef i) c2 t2).(arity g c2 t2 a0)
                (H2) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i0:nat
                         .(getl i0 d (CHead d1 (Bind Abbr) u0))c2:C.t2:T.(fsubst0 i0 u0 d u c2 t2)(arity g c2 t2 a0)
                    assume d1C
                    assume u0T
                    assume i0nat
                    suppose H3getl i0 c (CHead d1 (Bind Abbr) u0)
                    assume c2C
                    assume t2T
                    suppose H4fsubst0 i0 u0 c (TLRef i) c2 t2
                      (H_x
                         by (fsubst0_gen_base . . . . . . H4)

                            or3
                              land (eq C c c2) (subst0 i0 u0 (TLRef i) t2)
                              land (eq T (TLRef i) t2) (csubst0 i0 u0 c c2)
                              land (subst0 i0 u0 (TLRef i) t2) (csubst0 i0 u0 c c2)
                      end of H_x
                      (H5consider H_x
                      we proceed by induction on H5 to prove arity g c2 t2 a0
                         case or3_intro0 : H6:land (eq C c c2) (subst0 i0 u0 (TLRef i) t2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H6 to prove arity g c2 t2 a0
                                  case conj : H7:eq C c c2 H8:subst0 i0 u0 (TLRef i) t2 
                                     the thesis becomes arity g c2 t2 a0
                                        we proceed by induction on H7 to prove arity g c2 t2 a0
                                           case refl_equal : 
                                              the thesis becomes arity g c t2 a0
                                                 by (subst0_gen_lref . . . . H8)
                                                 we proved land (eq nat i i0) (eq T t2 (lift (S i) O u0))
                                                 we proceed by induction on the previous result to prove arity g c t2 a0
                                                    case conj : H9:eq nat i i0 H10:eq T t2 (lift (S i) O u0) 
                                                       the thesis becomes arity g c t2 a0
                                                          (H11
                                                             by (eq_ind_r . . . H3 . H9)
getl i c (CHead d1 (Bind Abbr) u0)
                                                          end of H11
                                                          (H12
                                                             by (getl_mono . . . H0 . H11)
                                                             we proved eq C (CHead d (Bind Abbr) u) (CHead d1 (Bind Abbr) u0)
                                                             we proceed by induction on the previous result to prove getl i c (CHead d1 (Bind Abbr) u0)
                                                                case refl_equal : 
                                                                   the thesis becomes the hypothesis H0
getl i c (CHead d1 (Bind Abbr) u0)
                                                          end of H12
                                                          (H13
                                                             by (getl_mono . . . H0 . H11)
                                                             we proved eq C (CHead d (Bind Abbr) u) (CHead d1 (Bind Abbr) u0)
                                                             by (f_equal . . . . . previous)
                                                             we proved 
                                                                eq
                                                                  C
                                                                  <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                                  <λ:C.C> CASE CHead d1 (Bind Abbr) u0 OF CSort d | CHead c0  c0

                                                                eq
                                                                  C
                                                                  λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d (Bind Abbr) u)
                                                                  λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d1 (Bind Abbr) u0)
                                                          end of H13
                                                          (h1
                                                             (H14
                                                                by (getl_mono . . . H0 . H11)
                                                                we proved eq C (CHead d (Bind Abbr) u) (CHead d1 (Bind Abbr) u0)
                                                                by (f_equal . . . . . previous)
                                                                we proved 
                                                                   eq
                                                                     T
                                                                     <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                     <λ:C.T> CASE CHead d1 (Bind Abbr) u0 OF CSort u | CHead   tt

                                                                   eq
                                                                     T
                                                                     λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d (Bind Abbr) u)
                                                                     λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d1 (Bind Abbr) u0)
                                                             end of H14
                                                             suppose H15eq C d d1
                                                                (H16
                                                                   consider H14
                                                                   we proved 
                                                                      eq
                                                                        T
                                                                        <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                        <λ:C.T> CASE CHead d1 (Bind Abbr) u0 OF CSort u | CHead   tt
                                                                   that is equivalent to eq T u u0
                                                                   by (eq_ind_r . . . H12 . previous)
getl i c (CHead d1 (Bind Abbr) u)
                                                                end of H16
                                                                consider H14
                                                                we proved 
                                                                   eq
                                                                     T
                                                                     <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                     <λ:C.T> CASE CHead d1 (Bind Abbr) u0 OF CSort u | CHead   tt
                                                                that is equivalent to eq T u u0
                                                                we proceed by induction on the previous result to prove arity g c (lift (S i) O u0) a0
                                                                   case refl_equal : 
                                                                      the thesis becomes arity g c (lift (S i) O u) a0
                                                                         (H17
                                                                            by (eq_ind_r . . . H16 . H15)
getl i c (CHead d (Bind Abbr) u)
                                                                         end of H17
                                                                         by (getl_drop . . . . . H17)
                                                                         we proved drop (S i) O c d
                                                                         by (arity_lift . . . . H1 . . . previous)
arity g c (lift (S i) O u) a0
                                                                we proved arity g c (lift (S i) O u0) a0
(eq C d d1)(arity g c (lift (S i) O u0) a0)
                                                          end of h1
                                                          (h2
                                                             consider H13
                                                             we proved 
                                                                eq
                                                                  C
                                                                  <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                                  <λ:C.C> CASE CHead d1 (Bind Abbr) u0 OF CSort d | CHead c0  c0
eq C d d1
                                                          end of h2
                                                          by (h1 h2)
                                                          we proved arity g c (lift (S i) O u0) a0
                                                          by (eq_ind_r . . . previous . H10)
arity g c t2 a0
arity g c t2 a0
arity g c2 t2 a0
arity g c2 t2 a0
                         case or3_intro1 : H6:land (eq T (TLRef i) t2) (csubst0 i0 u0 c c2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H6 to prove arity g c2 t2 a0
                                  case conj : H7:eq T (TLRef i) t2 H8:csubst0 i0 u0 c c2 
                                     the thesis becomes arity g c2 t2 a0
                                        we proceed by induction on H7 to prove arity g c2 t2 a0
                                           case refl_equal : 
                                              the thesis becomes arity g c2 (TLRef i) a0
                                                 (h1
                                                    suppose H9lt i i0
                                                       (H10
                                                          by (csubst0_getl_lt . . H9 . . . H8 . H0)

                                                             or4
                                                               getl i c2 (CHead d (Bind Abbr) u)
                                                               ex3_4
                                                                 B
                                                                 C
                                                                 T
                                                                 T
                                                                 λb:B.λe0:C.λu:T.λ:T.eq C (CHead d (Bind Abbr) u) (CHead e0 (Bind b) u)
                                                                 λb:B.λe0:C.λ:T.λw:T.getl i c2 (CHead e0 (Bind b) w)
                                                                 λ:B.λ:C.λu:T.λw:T.subst0 (minus i0 (S i)) u0 u w
                                                               ex3_4
                                                                 B
                                                                 C
                                                                 C
                                                                 T
                                                                 λb:B.λe1:C.λ:C.λu:T.eq C (CHead d (Bind Abbr) u) (CHead e1 (Bind b) u)
                                                                 λb:B.λ:C.λe2:C.λu:T.getl i c2 (CHead e2 (Bind b) u)
                                                                 λ:B.λe1:C.λe2:C.λ:T.csubst0 (minus i0 (S i)) u0 e1 e2
                                                               ex4_5
                                                                 B
                                                                 C
                                                                 C
                                                                 T
                                                                 T
                                                                 λb:B.λe1:C.λ:C.λu:T.λ:T.eq C (CHead d (Bind Abbr) u) (CHead e1 (Bind b) u)
                                                                 λb:B.λ:C.λe2:C.λ:T.λw:T.getl i c2 (CHead e2 (Bind b) w)
                                                                 λ:B.λ:C.λ:C.λu:T.λw:T.subst0 (minus i0 (S i)) u0 u w
                                                                 λ:B.λe1:C.λe2:C.λ:T.λ:T.csubst0 (minus i0 (S i)) u0 e1 e2
                                                       end of H10
                                                       we proceed by induction on H10 to prove arity g c2 (TLRef i) a0
                                                          case or4_intro0 : H11:getl i c2 (CHead d (Bind Abbr) u) 
                                                             the thesis becomes arity g c2 (TLRef i) a0
                                                                by (arity_abbr . . . . . H11 . H1)
arity g c2 (TLRef i) a0
                                                          case or4_intro1 : H11:ex3_4 B C T T λb:B.λe0:C.λu1:T.λ:T.eq C (CHead d (Bind Abbr) u) (CHead e0 (Bind b) u1) λb:B.λe0:C.λ:T.λw:T.getl i c2 (CHead e0 (Bind b) w) λ:B.λ:C.λu1:T.λw:T.subst0 (minus i0 (S i)) u0 u1 w 
                                                             the thesis becomes arity g c2 (TLRef i) a0
                                                                we proceed by induction on H11 to prove arity g c2 (TLRef i) a0
                                                                   case ex3_4_intro : x0:B x1:C x2:T x3:T H12:eq C (CHead d (Bind Abbr) u) (CHead x1 (Bind x0) x2) H13:getl i c2 (CHead x1 (Bind x0) x3) H14:subst0 (minus i0 (S i)) u0 x2 x3 
                                                                      the thesis becomes arity g c2 (TLRef i) a0
                                                                         (H15
                                                                            by (minus_x_Sy . . H9)
                                                                            we proved eq nat (minus i0 i) (S (minus i0 (S i)))
                                                                            we proceed by induction on the previous result to prove 
                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abbr) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                               case refl_equal : 
                                                                                  the thesis becomes 
                                                                                  getl
                                                                                    minus i0 i
                                                                                    CHead d (Bind Abbr) u
                                                                                    CHead d1 (Bind Abbr) u0
                                                                                     consider H9
                                                                                     we proved lt i i0
                                                                                     that is equivalent to le (S i) i0
                                                                                     by (le_S . . previous)
                                                                                     we proved le (S i) (S i0)
                                                                                     by (le_S_n . . previous)
                                                                                     we proved le i i0
                                                                                     by (getl_conf_le . . . H3 . . H0 previous)

                                                                                        getl
                                                                                          minus i0 i
                                                                                          CHead d (Bind Abbr) u
                                                                                          CHead d1 (Bind Abbr) u0

                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abbr) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                         end of H15
                                                                         (H16
                                                                            by (f_equal . . . . . H12)
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x2 OF CSort d | CHead c0  c0

                                                                               eq
                                                                                 C
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d (Bind Abbr) u)
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead x1 (Bind x0) x2)
                                                                         end of H16
                                                                         (h1
                                                                            (H17
                                                                               by (f_equal . . . . . H12)
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abbr) u OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x2 OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr

                                                                                  eq
                                                                                    B
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abbr
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                      CHead d (Bind Abbr) u
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abbr
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                      CHead x1 (Bind x0) x2
                                                                            end of H17
                                                                            (h1
                                                                               (H18
                                                                                  by (f_equal . . . . . H12)
                                                                                  we proved 
                                                                                     eq
                                                                                       T
                                                                                       <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                                       <λ:C.T> CASE CHead x1 (Bind x0) x2 OF CSort u | CHead   tt

                                                                                     eq
                                                                                       T
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d (Bind Abbr) u)
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead x1 (Bind x0) x2)
                                                                               end of H18
                                                                                suppose H19eq B Abbr x0
                                                                                suppose H20eq C d x1
                                                                                  (H21
                                                                                     consider H18
                                                                                     we proved 
                                                                                        eq
                                                                                          T
                                                                                          <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                                          <λ:C.T> CASE CHead x1 (Bind x0) x2 OF CSort u | CHead   tt
                                                                                     that is equivalent to eq T u x2
                                                                                     by (eq_ind_r . . . H14 . previous)
subst0 (minus i0 (S i)) u0 u x3
                                                                                  end of H21
                                                                                  (H22
                                                                                     by (eq_ind_r . . . H13 . H20)
getl i c2 (CHead d (Bind x0) x3)
                                                                                  end of H22
                                                                                  (H23
                                                                                     by (eq_ind_r . . . H22 . H19)
getl i c2 (CHead d (Bind Abbr) x3)
                                                                                  end of H23
                                                                                  (h1
                                                                                     by (getl_gen_S . . . . . H15)

                                                                                        getl (r (Bind Abbr) (minus i0 (S i))) d (CHead d1 (Bind Abbr) u0)
                                                                                  end of h1
                                                                                  (h2
                                                                                     consider H21
                                                                                     we proved subst0 (minus i0 (S i)) u0 u x3
                                                                                     that is equivalent to subst0 (r (Bind Abbr) (minus i0 (S i))) u0 u x3
                                                                                     by (fsubst0_snd . . . . . previous)
fsubst0 (r (Bind Abbr) (minus i0 (S i))) u0 d u d x3
                                                                                  end of h2
                                                                                  by (H2 . . . h1 . . h2)
                                                                                  we proved arity g d x3 a0
                                                                                  by (arity_abbr . . . . . H23 . previous)
                                                                                  we proved arity g c2 (TLRef i) a0
(eq B Abbr x0)(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                            end of h1
                                                                            (h2
                                                                               consider H17
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abbr) u OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x2 OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
eq B Abbr x0
                                                                            end of h2
                                                                            by (h1 h2)
(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                         end of h1
                                                                         (h2
                                                                            consider H16
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x2 OF CSort d | CHead c0  c0
eq C d x1
                                                                         end of h2
                                                                         by (h1 h2)
arity g c2 (TLRef i) a0
arity g c2 (TLRef i) a0
                                                          case or4_intro2 : H11:ex3_4 B C C T λb:B.λe1:C.λ:C.λu1:T.eq C (CHead d (Bind Abbr) u) (CHead e1 (Bind b) u1) λb:B.λ:C.λe2:C.λu1:T.getl i c2 (CHead e2 (Bind b) u1) λ:B.λe1:C.λe2:C.λ:T.csubst0 (minus i0 (S i)) u0 e1 e2 
                                                             the thesis becomes arity g c2 (TLRef i) a0
                                                                we proceed by induction on H11 to prove arity g c2 (TLRef i) a0
                                                                   case ex3_4_intro : x0:B x1:C x2:C x3:T H12:eq C (CHead d (Bind Abbr) u) (CHead x1 (Bind x0) x3) H13:getl i c2 (CHead x2 (Bind x0) x3) H14:csubst0 (minus i0 (S i)) u0 x1 x2 
                                                                      the thesis becomes arity g c2 (TLRef i) a0
                                                                         (H15
                                                                            by (minus_x_Sy . . H9)
                                                                            we proved eq nat (minus i0 i) (S (minus i0 (S i)))
                                                                            we proceed by induction on the previous result to prove 
                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abbr) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                               case refl_equal : 
                                                                                  the thesis becomes 
                                                                                  getl
                                                                                    minus i0 i
                                                                                    CHead d (Bind Abbr) u
                                                                                    CHead d1 (Bind Abbr) u0
                                                                                     consider H9
                                                                                     we proved lt i i0
                                                                                     that is equivalent to le (S i) i0
                                                                                     by (le_S . . previous)
                                                                                     we proved le (S i) (S i0)
                                                                                     by (le_S_n . . previous)
                                                                                     we proved le i i0
                                                                                     by (getl_conf_le . . . H3 . . H0 previous)

                                                                                        getl
                                                                                          minus i0 i
                                                                                          CHead d (Bind Abbr) u
                                                                                          CHead d1 (Bind Abbr) u0

                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abbr) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                         end of H15
                                                                         (H16
                                                                            by (f_equal . . . . . H12)
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x3 OF CSort d | CHead c0  c0

                                                                               eq
                                                                                 C
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d (Bind Abbr) u)
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead x1 (Bind x0) x3)
                                                                         end of H16
                                                                         (h1
                                                                            (H17
                                                                               by (f_equal . . . . . H12)
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abbr) u OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x3 OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr

                                                                                  eq
                                                                                    B
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abbr
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                      CHead d (Bind Abbr) u
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abbr
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                      CHead x1 (Bind x0) x3
                                                                            end of H17
                                                                            (h1
                                                                               (H18
                                                                                  by (f_equal . . . . . H12)
                                                                                  we proved 
                                                                                     eq
                                                                                       T
                                                                                       <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                                       <λ:C.T> CASE CHead x1 (Bind x0) x3 OF CSort u | CHead   tt

                                                                                     eq
                                                                                       T
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d (Bind Abbr) u)
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead x1 (Bind x0) x3)
                                                                               end of H18
                                                                                suppose H19eq B Abbr x0
                                                                                suppose H20eq C d x1
                                                                                  (H21
                                                                                     consider H18
                                                                                     we proved 
                                                                                        eq
                                                                                          T
                                                                                          <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                                          <λ:C.T> CASE CHead x1 (Bind x0) x3 OF CSort u | CHead   tt
                                                                                     that is equivalent to eq T u x3
                                                                                     by (eq_ind_r . . . H13 . previous)
getl i c2 (CHead x2 (Bind x0) u)
                                                                                  end of H21
                                                                                  (H22
                                                                                     by (eq_ind_r . . . H14 . H20)
csubst0 (minus i0 (S i)) u0 d x2
                                                                                  end of H22
                                                                                  (H23
                                                                                     by (eq_ind_r . . . H21 . H19)
getl i c2 (CHead x2 (Bind Abbr) u)
                                                                                  end of H23
                                                                                  (h1
                                                                                     by (getl_gen_S . . . . . H15)

                                                                                        getl (r (Bind Abbr) (minus i0 (S i))) d (CHead d1 (Bind Abbr) u0)
                                                                                  end of h1
                                                                                  (h2
                                                                                     consider H22
                                                                                     we proved csubst0 (minus i0 (S i)) u0 d x2
                                                                                     that is equivalent to csubst0 (r (Bind Abbr) (minus i0 (S i))) u0 d x2
                                                                                     by (fsubst0_fst . . . . . previous)
fsubst0 (r (Bind Abbr) (minus i0 (S i))) u0 d u x2 u
                                                                                  end of h2
                                                                                  by (H2 . . . h1 . . h2)
                                                                                  we proved arity g x2 u a0
                                                                                  by (arity_abbr . . . . . H23 . previous)
                                                                                  we proved arity g c2 (TLRef i) a0
(eq B Abbr x0)(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                            end of h1
                                                                            (h2
                                                                               consider H17
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abbr) u OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x3 OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
eq B Abbr x0
                                                                            end of h2
                                                                            by (h1 h2)
(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                         end of h1
                                                                         (h2
                                                                            consider H16
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x3 OF CSort d | CHead c0  c0
eq C d x1
                                                                         end of h2
                                                                         by (h1 h2)
arity g c2 (TLRef i) a0
arity g c2 (TLRef i) a0
                                                          case or4_intro3 : H11:ex4_5 B C C T T λb:B.λe1:C.λ:C.λu1:T.λ:T.eq C (CHead d (Bind Abbr) u) (CHead e1 (Bind b) u1) λb:B.λ:C.λe2:C.λ:T.λw:T.getl i c2 (CHead e2 (Bind b) w) λ:B.λ:C.λ:C.λu1:T.λw:T.subst0 (minus i0 (S i)) u0 u1 w λ:B.λe1:C.λe2:C.λ:T.λ:T.csubst0 (minus i0 (S i)) u0 e1 e2 
                                                             the thesis becomes arity g c2 (TLRef i) a0
                                                                we proceed by induction on H11 to prove arity g c2 (TLRef i) a0
                                                                   case ex4_5_intro : x0:B x1:C x2:C x3:T x4:T H12:eq C (CHead d (Bind Abbr) u) (CHead x1 (Bind x0) x3) H13:getl i c2 (CHead x2 (Bind x0) x4) H14:subst0 (minus i0 (S i)) u0 x3 x4 H15:csubst0 (minus i0 (S i)) u0 x1 x2 
                                                                      the thesis becomes arity g c2 (TLRef i) a0
                                                                         (H16
                                                                            by (minus_x_Sy . . H9)
                                                                            we proved eq nat (minus i0 i) (S (minus i0 (S i)))
                                                                            we proceed by induction on the previous result to prove 
                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abbr) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                               case refl_equal : 
                                                                                  the thesis becomes 
                                                                                  getl
                                                                                    minus i0 i
                                                                                    CHead d (Bind Abbr) u
                                                                                    CHead d1 (Bind Abbr) u0
                                                                                     consider H9
                                                                                     we proved lt i i0
                                                                                     that is equivalent to le (S i) i0
                                                                                     by (le_S . . previous)
                                                                                     we proved le (S i) (S i0)
                                                                                     by (le_S_n . . previous)
                                                                                     we proved le i i0
                                                                                     by (getl_conf_le . . . H3 . . H0 previous)

                                                                                        getl
                                                                                          minus i0 i
                                                                                          CHead d (Bind Abbr) u
                                                                                          CHead d1 (Bind Abbr) u0

                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abbr) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                         end of H16
                                                                         (H17
                                                                            by (f_equal . . . . . H12)
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x3 OF CSort d | CHead c0  c0

                                                                               eq
                                                                                 C
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d (Bind Abbr) u)
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead x1 (Bind x0) x3)
                                                                         end of H17
                                                                         (h1
                                                                            (H18
                                                                               by (f_equal . . . . . H12)
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abbr) u OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x3 OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr

                                                                                  eq
                                                                                    B
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abbr
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                      CHead d (Bind Abbr) u
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abbr
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                      CHead x1 (Bind x0) x3
                                                                            end of H18
                                                                            (h1
                                                                               (H19
                                                                                  by (f_equal . . . . . H12)
                                                                                  we proved 
                                                                                     eq
                                                                                       T
                                                                                       <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                                       <λ:C.T> CASE CHead x1 (Bind x0) x3 OF CSort u | CHead   tt

                                                                                     eq
                                                                                       T
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d (Bind Abbr) u)
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead x1 (Bind x0) x3)
                                                                               end of H19
                                                                                suppose H20eq B Abbr x0
                                                                                suppose H21eq C d x1
                                                                                  (H22
                                                                                     consider H19
                                                                                     we proved 
                                                                                        eq
                                                                                          T
                                                                                          <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                                                          <λ:C.T> CASE CHead x1 (Bind x0) x3 OF CSort u | CHead   tt
                                                                                     that is equivalent to eq T u x3
                                                                                     by (eq_ind_r . . . H14 . previous)
subst0 (minus i0 (S i)) u0 u x4
                                                                                  end of H22
                                                                                  (H23
                                                                                     by (eq_ind_r . . . H15 . H21)
csubst0 (minus i0 (S i)) u0 d x2
                                                                                  end of H23
                                                                                  (H24
                                                                                     by (eq_ind_r . . . H13 . H20)
getl i c2 (CHead x2 (Bind Abbr) x4)
                                                                                  end of H24
                                                                                  (h1
                                                                                     by (getl_gen_S . . . . . H16)

                                                                                        getl (r (Bind Abbr) (minus i0 (S i))) d (CHead d1 (Bind Abbr) u0)
                                                                                  end of h1
                                                                                  (h2
                                                                                     (h1
                                                                                        consider H22
                                                                                        we proved subst0 (minus i0 (S i)) u0 u x4
subst0 (r (Bind Abbr) (minus i0 (S i))) u0 u x4
                                                                                     end of h1
                                                                                     (h2
                                                                                        consider H23
                                                                                        we proved csubst0 (minus i0 (S i)) u0 d x2
csubst0 (r (Bind Abbr) (minus i0 (S i))) u0 d x2
                                                                                     end of h2
                                                                                     by (fsubst0_both . . . . . h1 . h2)
fsubst0 (r (Bind Abbr) (minus i0 (S i))) u0 d u x2 x4
                                                                                  end of h2
                                                                                  by (H2 . . . h1 . . h2)
                                                                                  we proved arity g x2 x4 a0
                                                                                  by (arity_abbr . . . . . H24 . previous)
                                                                                  we proved arity g c2 (TLRef i) a0
(eq B Abbr x0)(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                            end of h1
                                                                            (h2
                                                                               consider H18
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abbr) u OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x3 OF
                                                                                        CSort Abbr
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abbr
eq B Abbr x0
                                                                            end of h2
                                                                            by (h1 h2)
(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                         end of h1
                                                                         (h2
                                                                            consider H17
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x3 OF CSort d | CHead c0  c0
eq C d x1
                                                                         end of h2
                                                                         by (h1 h2)
arity g c2 (TLRef i) a0
arity g c2 (TLRef i) a0
                                                       we proved arity g c2 (TLRef i) a0
(lt i i0)(arity g c2 (TLRef i) a0)
                                                 end of h1
                                                 (h2
                                                    suppose H9le i0 i
                                                       by (csubst0_getl_ge . . H9 . . . H8 . H0)
                                                       we proved getl i c2 (CHead d (Bind Abbr) u)
                                                       by (arity_abbr . . . . . previous . H1)
                                                       we proved arity g c2 (TLRef i) a0
(le i0 i)(arity g c2 (TLRef i) a0)
                                                 end of h2
                                                 by (lt_le_e . . . h1 h2)
arity g c2 (TLRef i) a0
arity g c2 t2 a0
arity g c2 t2 a0
                         case or3_intro2 : H6:land (subst0 i0 u0 (TLRef i) t2) (csubst0 i0 u0 c c2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H6 to prove arity g c2 t2 a0
                                  case conj : H7:subst0 i0 u0 (TLRef i) t2 H8:csubst0 i0 u0 c c2 
                                     the thesis becomes arity g c2 t2 a0
                                        by (subst0_gen_lref . . . . H7)
                                        we proved land (eq nat i i0) (eq T t2 (lift (S i) O u0))
                                        we proceed by induction on the previous result to prove arity g c2 t2 a0
                                           case conj : H9:eq nat i i0 H10:eq T t2 (lift (S i) O u0) 
                                              the thesis becomes arity g c2 t2 a0
                                                 (H11
                                                    by (eq_ind_r . . . H8 . H9)
csubst0 i u0 c c2
                                                 end of H11
                                                 (H12
                                                    by (eq_ind_r . . . H3 . H9)
getl i c (CHead d1 (Bind Abbr) u0)
                                                 end of H12
                                                 (H13
                                                    by (getl_mono . . . H0 . H12)
                                                    we proved eq C (CHead d (Bind Abbr) u) (CHead d1 (Bind Abbr) u0)
                                                    we proceed by induction on the previous result to prove getl i c (CHead d1 (Bind Abbr) u0)
                                                       case refl_equal : 
                                                          the thesis becomes the hypothesis H0
getl i c (CHead d1 (Bind Abbr) u0)
                                                 end of H13
                                                 (H14
                                                    by (getl_mono . . . H0 . H12)
                                                    we proved eq C (CHead d (Bind Abbr) u) (CHead d1 (Bind Abbr) u0)
                                                    by (f_equal . . . . . previous)
                                                    we proved 
                                                       eq
                                                         C
                                                         <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                         <λ:C.C> CASE CHead d1 (Bind Abbr) u0 OF CSort d | CHead c0  c0

                                                       eq
                                                         C
                                                         λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d (Bind Abbr) u)
                                                         λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d1 (Bind Abbr) u0)
                                                 end of H14
                                                 (h1
                                                    (H15
                                                       by (getl_mono . . . H0 . H12)
                                                       we proved eq C (CHead d (Bind Abbr) u) (CHead d1 (Bind Abbr) u0)
                                                       by (f_equal . . . . . previous)
                                                       we proved 
                                                          eq
                                                            T
                                                            <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                            <λ:C.T> CASE CHead d1 (Bind Abbr) u0 OF CSort u | CHead   tt

                                                          eq
                                                            T
                                                            λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d (Bind Abbr) u)
                                                            λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d1 (Bind Abbr) u0)
                                                    end of H15
                                                    suppose H16eq C d d1
                                                       (H17
                                                          consider H15
                                                          we proved 
                                                             eq
                                                               T
                                                               <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                               <λ:C.T> CASE CHead d1 (Bind Abbr) u0 OF CSort u | CHead   tt
                                                          that is equivalent to eq T u u0
                                                          by (eq_ind_r . . . H13 . previous)
getl i c (CHead d1 (Bind Abbr) u)
                                                       end of H17
                                                       (H18
                                                          consider H15
                                                          we proved 
                                                             eq
                                                               T
                                                               <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                               <λ:C.T> CASE CHead d1 (Bind Abbr) u0 OF CSort u | CHead   tt
                                                          that is equivalent to eq T u u0
                                                          by (eq_ind_r . . . H11 . previous)
csubst0 i u c c2
                                                       end of H18
                                                       consider H15
                                                       we proved 
                                                          eq
                                                            T
                                                            <λ:C.T> CASE CHead d (Bind Abbr) u OF CSort u | CHead   tt
                                                            <λ:C.T> CASE CHead d1 (Bind Abbr) u0 OF CSort u | CHead   tt
                                                       that is equivalent to eq T u u0
                                                       we proceed by induction on the previous result to prove arity g c2 (lift (S i) O u0) a0
                                                          case refl_equal : 
                                                             the thesis becomes arity g c2 (lift (S i) O u) a0
                                                                (H19
                                                                   by (eq_ind_r . . . H17 . H16)
getl i c (CHead d (Bind Abbr) u)
                                                                end of H19
                                                                by (le_n .)
                                                                we proved le i i
                                                                by (csubst0_getl_ge . . previous . . . H18 . H19)
                                                                we proved getl i c2 (CHead d (Bind Abbr) u)
                                                                by (getl_drop . . . . . previous)
                                                                we proved drop (S i) O c2 d
                                                                by (arity_lift . . . . H1 . . . previous)
arity g c2 (lift (S i) O u) a0
                                                       we proved arity g c2 (lift (S i) O u0) a0
(eq C d d1)(arity g c2 (lift (S i) O u0) a0)
                                                 end of h1
                                                 (h2
                                                    consider H14
                                                    we proved 
                                                       eq
                                                         C
                                                         <λ:C.C> CASE CHead d (Bind Abbr) u OF CSort d | CHead c0  c0
                                                         <λ:C.C> CASE CHead d1 (Bind Abbr) u0 OF CSort d | CHead c0  c0
eq C d d1
                                                 end of h2
                                                 by (h1 h2)
                                                 we proved arity g c2 (lift (S i) O u0) a0
                                                 by (eq_ind_r . . . previous . H10)
arity g c2 t2 a0
arity g c2 t2 a0
arity g c2 t2 a0
                      we proved arity g c2 t2 a0

                      d1:C
                        .u0:T.i0:nat.H3:(getl i0 c (CHead d1 (Bind Abbr) u0)).c2:C.t2:T.H4:(fsubst0 i0 u0 c (TLRef i) c2 t2).(arity g c2 t2 a0)
             case arity_abst : c:C d:C u:T i:nat H0:getl i c (CHead d (Bind Abst) u) a0:A H1:arity g d u (asucc g a0) 
                the thesis becomes 
                d1:C
                  .u0:T.i0:nat.H3:(getl i0 c (CHead d1 (Bind Abbr) u0)).c2:C.t2:T.H4:(fsubst0 i0 u0 c (TLRef i) c2 t2).(arity g c2 t2 a0)
                (H2) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i0:nat
                         .getl i0 d (CHead d1 (Bind Abbr) u0)
                           c2:C.t2:T.(fsubst0 i0 u0 d u c2 t2)(arity g c2 t2 (asucc g a0))
                    assume d1C
                    assume u0T
                    assume i0nat
                    suppose H3getl i0 c (CHead d1 (Bind Abbr) u0)
                    assume c2C
                    assume t2T
                    suppose H4fsubst0 i0 u0 c (TLRef i) c2 t2
                      (H_x
                         by (fsubst0_gen_base . . . . . . H4)

                            or3
                              land (eq C c c2) (subst0 i0 u0 (TLRef i) t2)
                              land (eq T (TLRef i) t2) (csubst0 i0 u0 c c2)
                              land (subst0 i0 u0 (TLRef i) t2) (csubst0 i0 u0 c c2)
                      end of H_x
                      (H5consider H_x
                      we proceed by induction on H5 to prove arity g c2 t2 a0
                         case or3_intro0 : H6:land (eq C c c2) (subst0 i0 u0 (TLRef i) t2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H6 to prove arity g c2 t2 a0
                                  case conj : H7:eq C c c2 H8:subst0 i0 u0 (TLRef i) t2 
                                     the thesis becomes arity g c2 t2 a0
                                        we proceed by induction on H7 to prove arity g c2 t2 a0
                                           case refl_equal : 
                                              the thesis becomes arity g c t2 a0
                                                 by (subst0_gen_lref . . . . H8)
                                                 we proved land (eq nat i i0) (eq T t2 (lift (S i) O u0))
                                                 we proceed by induction on the previous result to prove arity g c t2 a0
                                                    case conj : H9:eq nat i i0 H10:eq T t2 (lift (S i) O u0) 
                                                       the thesis becomes arity g c t2 a0
                                                          (H11
                                                             by (eq_ind_r . . . H3 . H9)
getl i c (CHead d1 (Bind Abbr) u0)
                                                          end of H11
                                                          (H13
                                                             by (getl_mono . . . H0 . H11)
                                                             we proved eq C (CHead d (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                             we proceed by induction on the previous result to prove 
                                                                <λ:C.Prop>
                                                                  CASE CHead d1 (Bind Abbr) u0 OF
                                                                    CSort False
                                                                  | CHead  k 
                                                                        <λ:K.Prop>
                                                                          CASE k OF
                                                                            Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                          | Flat False
                                                                case refl_equal : 
                                                                   the thesis becomes 
                                                                   <λ:C.Prop>
                                                                     CASE CHead d (Bind Abst) u OF
                                                                       CSort False
                                                                     | CHead  k 
                                                                           <λ:K.Prop>
                                                                             CASE k OF
                                                                               Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                             | Flat False
                                                                      consider I
                                                                      we proved True

                                                                         <λ:C.Prop>
                                                                           CASE CHead d (Bind Abst) u OF
                                                                             CSort False
                                                                           | CHead  k 
                                                                                 <λ:K.Prop>
                                                                                   CASE k OF
                                                                                     Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                                   | Flat False

                                                                <λ:C.Prop>
                                                                  CASE CHead d1 (Bind Abbr) u0 OF
                                                                    CSort False
                                                                  | CHead  k 
                                                                        <λ:K.Prop>
                                                                          CASE k OF
                                                                            Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                          | Flat False
                                                          end of H13
                                                          consider H13
                                                          we proved 
                                                             <λ:C.Prop>
                                                               CASE CHead d1 (Bind Abbr) u0 OF
                                                                 CSort False
                                                               | CHead  k 
                                                                     <λ:K.Prop>
                                                                       CASE k OF
                                                                         Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                       | Flat False
                                                          that is equivalent to False
                                                          we proceed by induction on the previous result to prove arity g c (lift (S i) O u0) a0
                                                          we proved arity g c (lift (S i) O u0) a0
                                                          by (eq_ind_r . . . previous . H10)
arity g c t2 a0
arity g c t2 a0
arity g c2 t2 a0
arity g c2 t2 a0
                         case or3_intro1 : H6:land (eq T (TLRef i) t2) (csubst0 i0 u0 c c2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H6 to prove arity g c2 t2 a0
                                  case conj : H7:eq T (TLRef i) t2 H8:csubst0 i0 u0 c c2 
                                     the thesis becomes arity g c2 t2 a0
                                        we proceed by induction on H7 to prove arity g c2 t2 a0
                                           case refl_equal : 
                                              the thesis becomes arity g c2 (TLRef i) a0
                                                 (h1
                                                    suppose H9lt i i0
                                                       (H10
                                                          by (csubst0_getl_lt . . H9 . . . H8 . H0)

                                                             or4
                                                               getl i c2 (CHead d (Bind Abst) u)
                                                               ex3_4
                                                                 B
                                                                 C
                                                                 T
                                                                 T
                                                                 λb:B.λe0:C.λu:T.λ:T.eq C (CHead d (Bind Abst) u) (CHead e0 (Bind b) u)
                                                                 λb:B.λe0:C.λ:T.λw:T.getl i c2 (CHead e0 (Bind b) w)
                                                                 λ:B.λ:C.λu:T.λw:T.subst0 (minus i0 (S i)) u0 u w
                                                               ex3_4
                                                                 B
                                                                 C
                                                                 C
                                                                 T
                                                                 λb:B.λe1:C.λ:C.λu:T.eq C (CHead d (Bind Abst) u) (CHead e1 (Bind b) u)
                                                                 λb:B.λ:C.λe2:C.λu:T.getl i c2 (CHead e2 (Bind b) u)
                                                                 λ:B.λe1:C.λe2:C.λ:T.csubst0 (minus i0 (S i)) u0 e1 e2
                                                               ex4_5
                                                                 B
                                                                 C
                                                                 C
                                                                 T
                                                                 T
                                                                 λb:B.λe1:C.λ:C.λu:T.λ:T.eq C (CHead d (Bind Abst) u) (CHead e1 (Bind b) u)
                                                                 λb:B.λ:C.λe2:C.λ:T.λw:T.getl i c2 (CHead e2 (Bind b) w)
                                                                 λ:B.λ:C.λ:C.λu:T.λw:T.subst0 (minus i0 (S i)) u0 u w
                                                                 λ:B.λe1:C.λe2:C.λ:T.λ:T.csubst0 (minus i0 (S i)) u0 e1 e2
                                                       end of H10
                                                       we proceed by induction on H10 to prove arity g c2 (TLRef i) a0
                                                          case or4_intro0 : H11:getl i c2 (CHead d (Bind Abst) u) 
                                                             the thesis becomes arity g c2 (TLRef i) a0
                                                                by (arity_abst . . . . . H11 . H1)
arity g c2 (TLRef i) a0
                                                          case or4_intro1 : H11:ex3_4 B C T T λb:B.λe0:C.λu1:T.λ:T.eq C (CHead d (Bind Abst) u) (CHead e0 (Bind b) u1) λb:B.λe0:C.λ:T.λw:T.getl i c2 (CHead e0 (Bind b) w) λ:B.λ:C.λu1:T.λw:T.subst0 (minus i0 (S i)) u0 u1 w 
                                                             the thesis becomes arity g c2 (TLRef i) a0
                                                                we proceed by induction on H11 to prove arity g c2 (TLRef i) a0
                                                                   case ex3_4_intro : x0:B x1:C x2:T x3:T H12:eq C (CHead d (Bind Abst) u) (CHead x1 (Bind x0) x2) H13:getl i c2 (CHead x1 (Bind x0) x3) H14:subst0 (minus i0 (S i)) u0 x2 x3 
                                                                      the thesis becomes arity g c2 (TLRef i) a0
                                                                         (H15
                                                                            by (minus_x_Sy . . H9)
                                                                            we proved eq nat (minus i0 i) (S (minus i0 (S i)))
                                                                            we proceed by induction on the previous result to prove 
                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abst) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                               case refl_equal : 
                                                                                  the thesis becomes 
                                                                                  getl
                                                                                    minus i0 i
                                                                                    CHead d (Bind Abst) u
                                                                                    CHead d1 (Bind Abbr) u0
                                                                                     consider H9
                                                                                     we proved lt i i0
                                                                                     that is equivalent to le (S i) i0
                                                                                     by (le_S . . previous)
                                                                                     we proved le (S i) (S i0)
                                                                                     by (le_S_n . . previous)
                                                                                     we proved le i i0
                                                                                     by (getl_conf_le . . . H3 . . H0 previous)

                                                                                        getl
                                                                                          minus i0 i
                                                                                          CHead d (Bind Abst) u
                                                                                          CHead d1 (Bind Abbr) u0

                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abst) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                         end of H15
                                                                         (H16
                                                                            by (f_equal . . . . . H12)
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abst) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x2 OF CSort d | CHead c0  c0

                                                                               eq
                                                                                 C
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d (Bind Abst) u)
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead x1 (Bind x0) x2)
                                                                         end of H16
                                                                         (h1
                                                                            (H17
                                                                               by (f_equal . . . . . H12)
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abst) u OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x2 OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst

                                                                                  eq
                                                                                    B
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abst
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                      CHead d (Bind Abst) u
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abst
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                      CHead x1 (Bind x0) x2
                                                                            end of H17
                                                                            (h1
                                                                               (H18
                                                                                  by (f_equal . . . . . H12)
                                                                                  we proved 
                                                                                     eq
                                                                                       T
                                                                                       <λ:C.T> CASE CHead d (Bind Abst) u OF CSort u | CHead   tt
                                                                                       <λ:C.T> CASE CHead x1 (Bind x0) x2 OF CSort u | CHead   tt

                                                                                     eq
                                                                                       T
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d (Bind Abst) u)
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead x1 (Bind x0) x2)
                                                                               end of H18
                                                                                suppose H19eq B Abst x0
                                                                                suppose H20eq C d x1
                                                                                  (H21
                                                                                     consider H18
                                                                                     we proved 
                                                                                        eq
                                                                                          T
                                                                                          <λ:C.T> CASE CHead d (Bind Abst) u OF CSort u | CHead   tt
                                                                                          <λ:C.T> CASE CHead x1 (Bind x0) x2 OF CSort u | CHead   tt
                                                                                     that is equivalent to eq T u x2
                                                                                     by (eq_ind_r . . . H14 . previous)
subst0 (minus i0 (S i)) u0 u x3
                                                                                  end of H21
                                                                                  (H22
                                                                                     by (eq_ind_r . . . H13 . H20)
getl i c2 (CHead d (Bind x0) x3)
                                                                                  end of H22
                                                                                  (H23
                                                                                     by (eq_ind_r . . . H22 . H19)
getl i c2 (CHead d (Bind Abst) x3)
                                                                                  end of H23
                                                                                  (h1
                                                                                     by (getl_gen_S . . . . . H15)

                                                                                        getl (r (Bind Abst) (minus i0 (S i))) d (CHead d1 (Bind Abbr) u0)
                                                                                  end of h1
                                                                                  (h2
                                                                                     consider H21
                                                                                     we proved subst0 (minus i0 (S i)) u0 u x3
                                                                                     that is equivalent to subst0 (r (Bind Abst) (minus i0 (S i))) u0 u x3
                                                                                     by (fsubst0_snd . . . . . previous)
fsubst0 (r (Bind Abst) (minus i0 (S i))) u0 d u d x3
                                                                                  end of h2
                                                                                  by (H2 . . . h1 . . h2)
                                                                                  we proved arity g d x3 (asucc g a0)
                                                                                  by (arity_abst . . . . . H23 . previous)
                                                                                  we proved arity g c2 (TLRef i) a0
(eq B Abst x0)(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                            end of h1
                                                                            (h2
                                                                               consider H17
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abst) u OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x2 OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
eq B Abst x0
                                                                            end of h2
                                                                            by (h1 h2)
(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                         end of h1
                                                                         (h2
                                                                            consider H16
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abst) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x2 OF CSort d | CHead c0  c0
eq C d x1
                                                                         end of h2
                                                                         by (h1 h2)
arity g c2 (TLRef i) a0
arity g c2 (TLRef i) a0
                                                          case or4_intro2 : H11:ex3_4 B C C T λb:B.λe1:C.λ:C.λu1:T.eq C (CHead d (Bind Abst) u) (CHead e1 (Bind b) u1) λb:B.λ:C.λe2:C.λu1:T.getl i c2 (CHead e2 (Bind b) u1) λ:B.λe1:C.λe2:C.λ:T.csubst0 (minus i0 (S i)) u0 e1 e2 
                                                             the thesis becomes arity g c2 (TLRef i) a0
                                                                we proceed by induction on H11 to prove arity g c2 (TLRef i) a0
                                                                   case ex3_4_intro : x0:B x1:C x2:C x3:T H12:eq C (CHead d (Bind Abst) u) (CHead x1 (Bind x0) x3) H13:getl i c2 (CHead x2 (Bind x0) x3) H14:csubst0 (minus i0 (S i)) u0 x1 x2 
                                                                      the thesis becomes arity g c2 (TLRef i) a0
                                                                         (H15
                                                                            by (minus_x_Sy . . H9)
                                                                            we proved eq nat (minus i0 i) (S (minus i0 (S i)))
                                                                            we proceed by induction on the previous result to prove 
                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abst) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                               case refl_equal : 
                                                                                  the thesis becomes 
                                                                                  getl
                                                                                    minus i0 i
                                                                                    CHead d (Bind Abst) u
                                                                                    CHead d1 (Bind Abbr) u0
                                                                                     consider H9
                                                                                     we proved lt i i0
                                                                                     that is equivalent to le (S i) i0
                                                                                     by (le_S . . previous)
                                                                                     we proved le (S i) (S i0)
                                                                                     by (le_S_n . . previous)
                                                                                     we proved le i i0
                                                                                     by (getl_conf_le . . . H3 . . H0 previous)

                                                                                        getl
                                                                                          minus i0 i
                                                                                          CHead d (Bind Abst) u
                                                                                          CHead d1 (Bind Abbr) u0

                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abst) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                         end of H15
                                                                         (H16
                                                                            by (f_equal . . . . . H12)
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abst) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x3 OF CSort d | CHead c0  c0

                                                                               eq
                                                                                 C
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d (Bind Abst) u)
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead x1 (Bind x0) x3)
                                                                         end of H16
                                                                         (h1
                                                                            (H17
                                                                               by (f_equal . . . . . H12)
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abst) u OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x3 OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst

                                                                                  eq
                                                                                    B
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abst
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                      CHead d (Bind Abst) u
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abst
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                      CHead x1 (Bind x0) x3
                                                                            end of H17
                                                                            (h1
                                                                               (H18
                                                                                  by (f_equal . . . . . H12)
                                                                                  we proved 
                                                                                     eq
                                                                                       T
                                                                                       <λ:C.T> CASE CHead d (Bind Abst) u OF CSort u | CHead   tt
                                                                                       <λ:C.T> CASE CHead x1 (Bind x0) x3 OF CSort u | CHead   tt

                                                                                     eq
                                                                                       T
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d (Bind Abst) u)
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead x1 (Bind x0) x3)
                                                                               end of H18
                                                                                suppose H19eq B Abst x0
                                                                                suppose H20eq C d x1
                                                                                  (H21
                                                                                     consider H18
                                                                                     we proved 
                                                                                        eq
                                                                                          T
                                                                                          <λ:C.T> CASE CHead d (Bind Abst) u OF CSort u | CHead   tt
                                                                                          <λ:C.T> CASE CHead x1 (Bind x0) x3 OF CSort u | CHead   tt
                                                                                     that is equivalent to eq T u x3
                                                                                     by (eq_ind_r . . . H13 . previous)
getl i c2 (CHead x2 (Bind x0) u)
                                                                                  end of H21
                                                                                  (H22
                                                                                     by (eq_ind_r . . . H14 . H20)
csubst0 (minus i0 (S i)) u0 d x2
                                                                                  end of H22
                                                                                  (H23
                                                                                     by (eq_ind_r . . . H21 . H19)
getl i c2 (CHead x2 (Bind Abst) u)
                                                                                  end of H23
                                                                                  (h1
                                                                                     by (getl_gen_S . . . . . H15)

                                                                                        getl (r (Bind Abst) (minus i0 (S i))) d (CHead d1 (Bind Abbr) u0)
                                                                                  end of h1
                                                                                  (h2
                                                                                     consider H22
                                                                                     we proved csubst0 (minus i0 (S i)) u0 d x2
                                                                                     that is equivalent to csubst0 (r (Bind Abst) (minus i0 (S i))) u0 d x2
                                                                                     by (fsubst0_fst . . . . . previous)
fsubst0 (r (Bind Abst) (minus i0 (S i))) u0 d u x2 u
                                                                                  end of h2
                                                                                  by (H2 . . . h1 . . h2)
                                                                                  we proved arity g x2 u (asucc g a0)
                                                                                  by (arity_abst . . . . . H23 . previous)
                                                                                  we proved arity g c2 (TLRef i) a0
(eq B Abst x0)(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                            end of h1
                                                                            (h2
                                                                               consider H17
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abst) u OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x3 OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
eq B Abst x0
                                                                            end of h2
                                                                            by (h1 h2)
(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                         end of h1
                                                                         (h2
                                                                            consider H16
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abst) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x3 OF CSort d | CHead c0  c0
eq C d x1
                                                                         end of h2
                                                                         by (h1 h2)
arity g c2 (TLRef i) a0
arity g c2 (TLRef i) a0
                                                          case or4_intro3 : H11:ex4_5 B C C T T λb:B.λe1:C.λ:C.λu1:T.λ:T.eq C (CHead d (Bind Abst) u) (CHead e1 (Bind b) u1) λb:B.λ:C.λe2:C.λ:T.λw:T.getl i c2 (CHead e2 (Bind b) w) λ:B.λ:C.λ:C.λu1:T.λw:T.subst0 (minus i0 (S i)) u0 u1 w λ:B.λe1:C.λe2:C.λ:T.λ:T.csubst0 (minus i0 (S i)) u0 e1 e2 
                                                             the thesis becomes arity g c2 (TLRef i) a0
                                                                we proceed by induction on H11 to prove arity g c2 (TLRef i) a0
                                                                   case ex4_5_intro : x0:B x1:C x2:C x3:T x4:T H12:eq C (CHead d (Bind Abst) u) (CHead x1 (Bind x0) x3) H13:getl i c2 (CHead x2 (Bind x0) x4) H14:subst0 (minus i0 (S i)) u0 x3 x4 H15:csubst0 (minus i0 (S i)) u0 x1 x2 
                                                                      the thesis becomes arity g c2 (TLRef i) a0
                                                                         (H16
                                                                            by (minus_x_Sy . . H9)
                                                                            we proved eq nat (minus i0 i) (S (minus i0 (S i)))
                                                                            we proceed by induction on the previous result to prove 
                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abst) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                               case refl_equal : 
                                                                                  the thesis becomes 
                                                                                  getl
                                                                                    minus i0 i
                                                                                    CHead d (Bind Abst) u
                                                                                    CHead d1 (Bind Abbr) u0
                                                                                     consider H9
                                                                                     we proved lt i i0
                                                                                     that is equivalent to le (S i) i0
                                                                                     by (le_S . . previous)
                                                                                     we proved le (S i) (S i0)
                                                                                     by (le_S_n . . previous)
                                                                                     we proved le i i0
                                                                                     by (getl_conf_le . . . H3 . . H0 previous)

                                                                                        getl
                                                                                          minus i0 i
                                                                                          CHead d (Bind Abst) u
                                                                                          CHead d1 (Bind Abbr) u0

                                                                               getl
                                                                                 S (minus i0 (S i))
                                                                                 CHead d (Bind Abst) u
                                                                                 CHead d1 (Bind Abbr) u0
                                                                         end of H16
                                                                         (H17
                                                                            by (f_equal . . . . . H12)
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abst) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x3 OF CSort d | CHead c0  c0

                                                                               eq
                                                                                 C
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead d (Bind Abst) u)
                                                                                 λe:C.<λ:C.C> CASE e OF CSort d | CHead c0  c0 (CHead x1 (Bind x0) x3)
                                                                         end of H17
                                                                         (h1
                                                                            (H18
                                                                               by (f_equal . . . . . H12)
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abst) u OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x3 OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst

                                                                                  eq
                                                                                    B
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abst
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                      CHead d (Bind Abst) u
                                                                                    λe:C
                                                                                        .<λ:C.B>
                                                                                          CASE e OF
                                                                                            CSort Abst
                                                                                          | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                      CHead x1 (Bind x0) x3
                                                                            end of H18
                                                                            (h1
                                                                               (H19
                                                                                  by (f_equal . . . . . H12)
                                                                                  we proved 
                                                                                     eq
                                                                                       T
                                                                                       <λ:C.T> CASE CHead d (Bind Abst) u OF CSort u | CHead   tt
                                                                                       <λ:C.T> CASE CHead x1 (Bind x0) x3 OF CSort u | CHead   tt

                                                                                     eq
                                                                                       T
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead d (Bind Abst) u)
                                                                                       λe:C.<λ:C.T> CASE e OF CSort u | CHead   tt (CHead x1 (Bind x0) x3)
                                                                               end of H19
                                                                                suppose H20eq B Abst x0
                                                                                suppose H21eq C d x1
                                                                                  (H22
                                                                                     consider H19
                                                                                     we proved 
                                                                                        eq
                                                                                          T
                                                                                          <λ:C.T> CASE CHead d (Bind Abst) u OF CSort u | CHead   tt
                                                                                          <λ:C.T> CASE CHead x1 (Bind x0) x3 OF CSort u | CHead   tt
                                                                                     that is equivalent to eq T u x3
                                                                                     by (eq_ind_r . . . H14 . previous)
subst0 (minus i0 (S i)) u0 u x4
                                                                                  end of H22
                                                                                  (H23
                                                                                     by (eq_ind_r . . . H15 . H21)
csubst0 (minus i0 (S i)) u0 d x2
                                                                                  end of H23
                                                                                  (H24
                                                                                     by (eq_ind_r . . . H13 . H20)
getl i c2 (CHead x2 (Bind Abst) x4)
                                                                                  end of H24
                                                                                  (h1
                                                                                     by (getl_gen_S . . . . . H16)

                                                                                        getl (r (Bind Abst) (minus i0 (S i))) d (CHead d1 (Bind Abbr) u0)
                                                                                  end of h1
                                                                                  (h2
                                                                                     (h1
                                                                                        consider H22
                                                                                        we proved subst0 (minus i0 (S i)) u0 u x4
subst0 (r (Bind Abst) (minus i0 (S i))) u0 u x4
                                                                                     end of h1
                                                                                     (h2
                                                                                        consider H23
                                                                                        we proved csubst0 (minus i0 (S i)) u0 d x2
csubst0 (r (Bind Abst) (minus i0 (S i))) u0 d x2
                                                                                     end of h2
                                                                                     by (fsubst0_both . . . . . h1 . h2)
fsubst0 (r (Bind Abst) (minus i0 (S i))) u0 d u x2 x4
                                                                                  end of h2
                                                                                  by (H2 . . . h1 . . h2)
                                                                                  we proved arity g x2 x4 (asucc g a0)
                                                                                  by (arity_abst . . . . . H24 . previous)
                                                                                  we proved arity g c2 (TLRef i) a0
(eq B Abst x0)(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                            end of h1
                                                                            (h2
                                                                               consider H18
                                                                               we proved 
                                                                                  eq
                                                                                    B
                                                                                    <λ:C.B>
                                                                                      CASE CHead d (Bind Abst) u OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
                                                                                    <λ:C.B>
                                                                                      CASE CHead x1 (Bind x0) x3 OF
                                                                                        CSort Abst
                                                                                      | CHead  k <λ:K.B> CASE k OF Bind bb | Flat Abst
eq B Abst x0
                                                                            end of h2
                                                                            by (h1 h2)
(eq C d x1)(arity g c2 (TLRef i) a0)
                                                                         end of h1
                                                                         (h2
                                                                            consider H17
                                                                            we proved 
                                                                               eq
                                                                                 C
                                                                                 <λ:C.C> CASE CHead d (Bind Abst) u OF CSort d | CHead c0  c0
                                                                                 <λ:C.C> CASE CHead x1 (Bind x0) x3 OF CSort d | CHead c0  c0
eq C d x1
                                                                         end of h2
                                                                         by (h1 h2)
arity g c2 (TLRef i) a0
arity g c2 (TLRef i) a0
                                                       we proved arity g c2 (TLRef i) a0
(lt i i0)(arity g c2 (TLRef i) a0)
                                                 end of h1
                                                 (h2
                                                    suppose H9le i0 i
                                                       by (csubst0_getl_ge . . H9 . . . H8 . H0)
                                                       we proved getl i c2 (CHead d (Bind Abst) u)
                                                       by (arity_abst . . . . . previous . H1)
                                                       we proved arity g c2 (TLRef i) a0
(le i0 i)(arity g c2 (TLRef i) a0)
                                                 end of h2
                                                 by (lt_le_e . . . h1 h2)
arity g c2 (TLRef i) a0
arity g c2 t2 a0
arity g c2 t2 a0
                         case or3_intro2 : H6:land (subst0 i0 u0 (TLRef i) t2) (csubst0 i0 u0 c c2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H6 to prove arity g c2 t2 a0
                                  case conj : H7:subst0 i0 u0 (TLRef i) t2 H8:csubst0 i0 u0 c c2 
                                     the thesis becomes arity g c2 t2 a0
                                        by (subst0_gen_lref . . . . H7)
                                        we proved land (eq nat i i0) (eq T t2 (lift (S i) O u0))
                                        we proceed by induction on the previous result to prove arity g c2 t2 a0
                                           case conj : H9:eq nat i i0 H10:eq T t2 (lift (S i) O u0) 
                                              the thesis becomes arity g c2 t2 a0
                                                 (H12
                                                    by (eq_ind_r . . . H3 . H9)
getl i c (CHead d1 (Bind Abbr) u0)
                                                 end of H12
                                                 (H14
                                                    by (getl_mono . . . H0 . H12)
                                                    we proved eq C (CHead d (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                    we proceed by induction on the previous result to prove 
                                                       <λ:C.Prop>
                                                         CASE CHead d1 (Bind Abbr) u0 OF
                                                           CSort False
                                                         | CHead  k 
                                                               <λ:K.Prop>
                                                                 CASE k OF
                                                                   Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                 | Flat False
                                                       case refl_equal : 
                                                          the thesis becomes 
                                                          <λ:C.Prop>
                                                            CASE CHead d (Bind Abst) u OF
                                                              CSort False
                                                            | CHead  k 
                                                                  <λ:K.Prop>
                                                                    CASE k OF
                                                                      Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                    | Flat False
                                                             consider I
                                                             we proved True

                                                                <λ:C.Prop>
                                                                  CASE CHead d (Bind Abst) u OF
                                                                    CSort False
                                                                  | CHead  k 
                                                                        <λ:K.Prop>
                                                                          CASE k OF
                                                                            Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                          | Flat False

                                                       <λ:C.Prop>
                                                         CASE CHead d1 (Bind Abbr) u0 OF
                                                           CSort False
                                                         | CHead  k 
                                                               <λ:K.Prop>
                                                                 CASE k OF
                                                                   Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                                 | Flat False
                                                 end of H14
                                                 consider H14
                                                 we proved 
                                                    <λ:C.Prop>
                                                      CASE CHead d1 (Bind Abbr) u0 OF
                                                        CSort False
                                                      | CHead  k 
                                                            <λ:K.Prop>
                                                              CASE k OF
                                                                Bind b<λ:B.Prop> CASE b OF AbbrFalse | AbstTrue | VoidFalse
                                                              | Flat False
                                                 that is equivalent to False
                                                 we proceed by induction on the previous result to prove arity g c2 (lift (S i) O u0) a0
                                                 we proved arity g c2 (lift (S i) O u0) a0
                                                 by (eq_ind_r . . . previous . H10)
arity g c2 t2 a0
arity g c2 t2 a0
arity g c2 t2 a0
                      we proved arity g c2 t2 a0

                      d1:C
                        .u0:T.i0:nat.H3:(getl i0 c (CHead d1 (Bind Abbr) u0)).c2:C.t2:T.H4:(fsubst0 i0 u0 c (TLRef i) c2 t2).(arity g c2 t2 a0)
             case arity_bind : b:B H0:not (eq B b Abst) c:C u:T a1:A H1:arity g c u a1 t:T a2:A :arity g (CHead c (Bind b) u) t a2 
                the thesis becomes 
                d1:C
                  .u0:T
                    .i:nat
                      .H5:getl i c (CHead d1 (Bind Abbr) u0)
                        .c2:C.t2:T.H6:(fsubst0 i u0 c (THead (Bind b) u t) c2 t2).(arity g c2 t2 a2)
                (H2) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i:nat
                         .(getl i c (CHead d1 (Bind Abbr) u0))c2:C.t2:T.(fsubst0 i u0 c u c2 t2)(arity g c2 t2 a1)
                (H4) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i:nat
                         .getl i (CHead c (Bind b) u) (CHead d1 (Bind Abbr) u0)
                           c2:C.t2:T.(fsubst0 i u0 (CHead c (Bind b) u) t c2 t2)(arity g c2 t2 a2)
                    assume d1C
                    assume u0T
                    assume inat
                    suppose H5getl i c (CHead d1 (Bind Abbr) u0)
                    assume c2C
                    assume t2T
                    suppose H6fsubst0 i u0 c (THead (Bind b) u t) c2 t2
                      (H_x
                         by (fsubst0_gen_base . . . . . . H6)

                            or3
                              land (eq C c c2) (subst0 i u0 (THead (Bind b) u t) t2)
                              land (eq T (THead (Bind b) u t) t2) (csubst0 i u0 c c2)
                              land (subst0 i u0 (THead (Bind b) u t) t2) (csubst0 i u0 c c2)
                      end of H_x
                      (H7consider H_x
                      we proceed by induction on H7 to prove arity g c2 t2 a2
                         case or3_intro0 : H8:land (eq C c c2) (subst0 i u0 (THead (Bind b) u t) t2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H8 to prove arity g c2 t2 a2
                                  case conj : H9:eq C c c2 H10:subst0 i u0 (THead (Bind b) u t) t2 
                                     the thesis becomes arity g c2 t2 a2
                                        we proceed by induction on H9 to prove arity g c2 t2 a2
                                           case refl_equal : 
                                              the thesis becomes arity g c t2 a2
                                                 by (subst0_gen_head . . . . . . H10)
                                                 we proved 
                                                    or3
                                                      ex2 T λu2:T.eq T t2 (THead (Bind b) u2 t) λu2:T.subst0 i u0 u u2
                                                      ex2 T λt2:T.eq T t2 (THead (Bind b) u t2) λt2:T.subst0 (s (Bind b) i) u0 t t2
                                                      ex3_2 T T λu2:T.λt2:T.eq T t2 (THead (Bind b) u2 t2) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt2:T.subst0 (s (Bind b) i) u0 t t2
                                                 we proceed by induction on the previous result to prove arity g c t2 a2
                                                    case or3_intro0 : H11:ex2 T λu2:T.eq T t2 (THead (Bind b) u2 t) λu2:T.subst0 i u0 u u2 
                                                       the thesis becomes arity g c t2 a2
                                                          we proceed by induction on H11 to prove arity g c t2 a2
                                                             case ex_intro2 : x:T H12:eq T t2 (THead (Bind b) x t) H13:subst0 i u0 u x 
                                                                the thesis becomes arity g c t2 a2
                                                                   (h1
                                                                      by (fsubst0_snd . . . . . H13)
                                                                      we proved fsubst0 i u0 c u c x
                                                                      by (H2 . . . H5 . . previous)
arity g c x a1
                                                                   end of h1
                                                                   (h2
                                                                      (h1
                                                                         by (clear_bind . . .)
                                                                         we proved clear (CHead c (Bind b) u) (CHead c (Bind b) u)
                                                                         by (getl_clear_bind . . . . previous . . H5)
getl (S i) (CHead c (Bind b) u) (CHead d1 (Bind Abbr) u0)
                                                                      end of h1
                                                                      (h2
                                                                         by (csubst0_snd_bind . . . . . H13 .)
                                                                         we proved csubst0 (S i) u0 (CHead c (Bind b) u) (CHead c (Bind b) x)
                                                                         by (fsubst0_fst . . . . . previous)
fsubst0 (S i) u0 (CHead c (Bind b) u) t (CHead c (Bind b) x) t
                                                                      end of h2
                                                                      by (H4 . . . h1 . . h2)
arity g (CHead c (Bind b) x) t a2
                                                                   end of h2
                                                                   by (arity_bind . . H0 . . . h1 . . h2)
                                                                   we proved arity g c (THead (Bind b) x t) a2
                                                                   by (eq_ind_r . . . previous . H12)
arity g c t2 a2
arity g c t2 a2
                                                    case or3_intro1 : H11:ex2 T λt3:T.eq T t2 (THead (Bind b) u t3) λt3:T.subst0 (s (Bind b) i) u0 t t3 
                                                       the thesis becomes arity g c t2 a2
                                                          we proceed by induction on H11 to prove arity g c t2 a2
                                                             case ex_intro2 : x:T H12:eq T t2 (THead (Bind b) u x) H13:subst0 (s (Bind b) i) u0 t x 
                                                                the thesis becomes arity g c t2 a2
                                                                   (h1
                                                                      by (clear_bind . . .)
                                                                      we proved clear (CHead c (Bind b) u) (CHead c (Bind b) u)
                                                                      by (getl_clear_bind . . . . previous . . H5)
getl (S i) (CHead c (Bind b) u) (CHead d1 (Bind Abbr) u0)
                                                                   end of h1
                                                                   (h2
                                                                      consider H13
                                                                      we proved subst0 (s (Bind b) i) u0 t x
                                                                      that is equivalent to subst0 (S i) u0 t x
                                                                      by (fsubst0_snd . . . . . previous)
fsubst0 (S i) u0 (CHead c (Bind b) u) t (CHead c (Bind b) u) x
                                                                   end of h2
                                                                   by (H4 . . . h1 . . h2)
                                                                   we proved arity g (CHead c (Bind b) u) x a2
                                                                   by (arity_bind . . H0 . . . H1 . . previous)
                                                                   we proved arity g c (THead (Bind b) u x) a2
                                                                   by (eq_ind_r . . . previous . H12)
arity g c t2 a2
arity g c t2 a2
                                                    case or3_intro2 : H11:ex3_2 T T λu2:T.λt3:T.eq T t2 (THead (Bind b) u2 t3) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt3:T.subst0 (s (Bind b) i) u0 t t3 
                                                       the thesis becomes arity g c t2 a2
                                                          we proceed by induction on H11 to prove arity g c t2 a2
                                                             case ex3_2_intro : x0:T x1:T H12:eq T t2 (THead (Bind b) x0 x1) H13:subst0 i u0 u x0 H14:subst0 (s (Bind b) i) u0 t x1 
                                                                the thesis becomes arity g c t2 a2
                                                                   (h1
                                                                      by (fsubst0_snd . . . . . H13)
                                                                      we proved fsubst0 i u0 c u c x0
                                                                      by (H2 . . . H5 . . previous)
arity g c x0 a1
                                                                   end of h1
                                                                   (h2
                                                                      (h1
                                                                         by (clear_bind . . .)
                                                                         we proved clear (CHead c (Bind b) u) (CHead c (Bind b) u)
                                                                         by (getl_clear_bind . . . . previous . . H5)
getl (S i) (CHead c (Bind b) u) (CHead d1 (Bind Abbr) u0)
                                                                      end of h1
                                                                      (h2
                                                                         (h1
                                                                            consider H14
                                                                            we proved subst0 (s (Bind b) i) u0 t x1
subst0 (S i) u0 t x1
                                                                         end of h1
                                                                         (h2
                                                                            by (csubst0_snd_bind . . . . . H13 .)
csubst0 (S i) u0 (CHead c (Bind b) u) (CHead c (Bind b) x0)
                                                                         end of h2
                                                                         by (fsubst0_both . . . . . h1 . h2)
fsubst0 (S i) u0 (CHead c (Bind b) u) t (CHead c (Bind b) x0) x1
                                                                      end of h2
                                                                      by (H4 . . . h1 . . h2)
arity g (CHead c (Bind b) x0) x1 a2
                                                                   end of h2
                                                                   by (arity_bind . . H0 . . . h1 . . h2)
                                                                   we proved arity g c (THead (Bind b) x0 x1) a2
                                                                   by (eq_ind_r . . . previous . H12)
arity g c t2 a2
arity g c t2 a2
arity g c t2 a2
arity g c2 t2 a2
arity g c2 t2 a2
                         case or3_intro1 : H8:land (eq T (THead (Bind b) u t) t2) (csubst0 i u0 c c2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H8 to prove arity g c2 t2 a2
                                  case conj : H9:eq T (THead (Bind b) u t) t2 H10:csubst0 i u0 c c2 
                                     the thesis becomes arity g c2 t2 a2
                                        we proceed by induction on H9 to prove arity g c2 t2 a2
                                           case refl_equal : 
                                              the thesis becomes arity g c2 (THead (Bind b) u t) a2
                                                 (h1
                                                    by (fsubst0_fst . . . . . H10)
                                                    we proved fsubst0 i u0 c u c2 u
                                                    by (H2 . . . H5 . . previous)
arity g c2 u a1
                                                 end of h1
                                                 (h2
                                                    (h1
                                                       by (clear_bind . . .)
                                                       we proved clear (CHead c (Bind b) u) (CHead c (Bind b) u)
                                                       by (getl_clear_bind . . . . previous . . H5)
getl (S i) (CHead c (Bind b) u) (CHead d1 (Bind Abbr) u0)
                                                    end of h1
                                                    (h2
                                                       by (csubst0_fst_bind . . . . . H10 .)
                                                       we proved csubst0 (S i) u0 (CHead c (Bind b) u) (CHead c2 (Bind b) u)
                                                       by (fsubst0_fst . . . . . previous)
fsubst0 (S i) u0 (CHead c (Bind b) u) t (CHead c2 (Bind b) u) t
                                                    end of h2
                                                    by (H4 . . . h1 . . h2)
arity g (CHead c2 (Bind b) u) t a2
                                                 end of h2
                                                 by (arity_bind . . H0 . . . h1 . . h2)
arity g c2 (THead (Bind b) u t) a2
arity g c2 t2 a2
arity g c2 t2 a2
                         case or3_intro2 : H8:land (subst0 i u0 (THead (Bind b) u t) t2) (csubst0 i u0 c c2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H8 to prove arity g c2 t2 a2
                                  case conj : H9:subst0 i u0 (THead (Bind b) u t) t2 H10:csubst0 i u0 c c2 
                                     the thesis becomes arity g c2 t2 a2
                                        by (subst0_gen_head . . . . . . H9)
                                        we proved 
                                           or3
                                             ex2 T λu2:T.eq T t2 (THead (Bind b) u2 t) λu2:T.subst0 i u0 u u2
                                             ex2 T λt2:T.eq T t2 (THead (Bind b) u t2) λt2:T.subst0 (s (Bind b) i) u0 t t2
                                             ex3_2 T T λu2:T.λt2:T.eq T t2 (THead (Bind b) u2 t2) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt2:T.subst0 (s (Bind b) i) u0 t t2
                                        we proceed by induction on the previous result to prove arity g c2 t2 a2
                                           case or3_intro0 : H11:ex2 T λu2:T.eq T t2 (THead (Bind b) u2 t) λu2:T.subst0 i u0 u u2 
                                              the thesis becomes arity g c2 t2 a2
                                                 we proceed by induction on H11 to prove arity g c2 t2 a2
                                                    case ex_intro2 : x:T H12:eq T t2 (THead (Bind b) x t) H13:subst0 i u0 u x 
                                                       the thesis becomes arity g c2 t2 a2
                                                          (h1
                                                             by (fsubst0_both . . . . . H13 . H10)
                                                             we proved fsubst0 i u0 c u c2 x
                                                             by (H2 . . . H5 . . previous)
arity g c2 x a1
                                                          end of h1
                                                          (h2
                                                             (h1
                                                                by (clear_bind . . .)
                                                                we proved clear (CHead c (Bind b) u) (CHead c (Bind b) u)
                                                                by (getl_clear_bind . . . . previous . . H5)
getl (S i) (CHead c (Bind b) u) (CHead d1 (Bind Abbr) u0)
                                                             end of h1
                                                             (h2
                                                                by (csubst0_both_bind . . . . . H13 . . H10)
                                                                we proved csubst0 (S i) u0 (CHead c (Bind b) u) (CHead c2 (Bind b) x)
                                                                by (fsubst0_fst . . . . . previous)
fsubst0 (S i) u0 (CHead c (Bind b) u) t (CHead c2 (Bind b) x) t
                                                             end of h2
                                                             by (H4 . . . h1 . . h2)
arity g (CHead c2 (Bind b) x) t a2
                                                          end of h2
                                                          by (arity_bind . . H0 . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Bind b) x t) a2
                                                          by (eq_ind_r . . . previous . H12)
arity g c2 t2 a2
arity g c2 t2 a2
                                           case or3_intro1 : H11:ex2 T λt3:T.eq T t2 (THead (Bind b) u t3) λt3:T.subst0 (s (Bind b) i) u0 t t3 
                                              the thesis becomes arity g c2 t2 a2
                                                 we proceed by induction on H11 to prove arity g c2 t2 a2
                                                    case ex_intro2 : x:T H12:eq T t2 (THead (Bind b) u x) H13:subst0 (s (Bind b) i) u0 t x 
                                                       the thesis becomes arity g c2 t2 a2
                                                          (h1
                                                             by (fsubst0_fst . . . . . H10)
                                                             we proved fsubst0 i u0 c u c2 u
                                                             by (H2 . . . H5 . . previous)
arity g c2 u a1
                                                          end of h1
                                                          (h2
                                                             (h1
                                                                by (clear_bind . . .)
                                                                we proved clear (CHead c (Bind b) u) (CHead c (Bind b) u)
                                                                by (getl_clear_bind . . . . previous . . H5)
getl (S i) (CHead c (Bind b) u) (CHead d1 (Bind Abbr) u0)
                                                             end of h1
                                                             (h2
                                                                (h1
                                                                   consider H13
                                                                   we proved subst0 (s (Bind b) i) u0 t x
subst0 (S i) u0 t x
                                                                end of h1
                                                                (h2
                                                                   by (csubst0_fst_bind . . . . . H10 .)
csubst0 (S i) u0 (CHead c (Bind b) u) (CHead c2 (Bind b) u)
                                                                end of h2
                                                                by (fsubst0_both . . . . . h1 . h2)
fsubst0 (S i) u0 (CHead c (Bind b) u) t (CHead c2 (Bind b) u) x
                                                             end of h2
                                                             by (H4 . . . h1 . . h2)
arity g (CHead c2 (Bind b) u) x a2
                                                          end of h2
                                                          by (arity_bind . . H0 . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Bind b) u x) a2
                                                          by (eq_ind_r . . . previous . H12)
arity g c2 t2 a2
arity g c2 t2 a2
                                           case or3_intro2 : H11:ex3_2 T T λu2:T.λt3:T.eq T t2 (THead (Bind b) u2 t3) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt3:T.subst0 (s (Bind b) i) u0 t t3 
                                              the thesis becomes arity g c2 t2 a2
                                                 we proceed by induction on H11 to prove arity g c2 t2 a2
                                                    case ex3_2_intro : x0:T x1:T H12:eq T t2 (THead (Bind b) x0 x1) H13:subst0 i u0 u x0 H14:subst0 (s (Bind b) i) u0 t x1 
                                                       the thesis becomes arity g c2 t2 a2
                                                          (h1
                                                             by (fsubst0_both . . . . . H13 . H10)
                                                             we proved fsubst0 i u0 c u c2 x0
                                                             by (H2 . . . H5 . . previous)
arity g c2 x0 a1
                                                          end of h1
                                                          (h2
                                                             (h1
                                                                by (clear_bind . . .)
                                                                we proved clear (CHead c (Bind b) u) (CHead c (Bind b) u)
                                                                by (getl_clear_bind . . . . previous . . H5)
getl (S i) (CHead c (Bind b) u) (CHead d1 (Bind Abbr) u0)
                                                             end of h1
                                                             (h2
                                                                (h1
                                                                   consider H14
                                                                   we proved subst0 (s (Bind b) i) u0 t x1
subst0 (S i) u0 t x1
                                                                end of h1
                                                                (h2
                                                                   by (csubst0_both_bind . . . . . H13 . . H10)
csubst0 (S i) u0 (CHead c (Bind b) u) (CHead c2 (Bind b) x0)
                                                                end of h2
                                                                by (fsubst0_both . . . . . h1 . h2)
fsubst0 (S i) u0 (CHead c (Bind b) u) t (CHead c2 (Bind b) x0) x1
                                                             end of h2
                                                             by (H4 . . . h1 . . h2)
arity g (CHead c2 (Bind b) x0) x1 a2
                                                          end of h2
                                                          by (arity_bind . . H0 . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Bind b) x0 x1) a2
                                                          by (eq_ind_r . . . previous . H12)
arity g c2 t2 a2
arity g c2 t2 a2
arity g c2 t2 a2
arity g c2 t2 a2
                      we proved arity g c2 t2 a2

                      d1:C
                        .u0:T
                          .i:nat
                            .H5:getl i c (CHead d1 (Bind Abbr) u0)
                              .c2:C.t2:T.H6:(fsubst0 i u0 c (THead (Bind b) u t) c2 t2).(arity g c2 t2 a2)
             case arity_head : c:C u:T a1:A H0:arity g c u (asucc g a1) t:T a2:A :arity g (CHead c (Bind Abst) u) t a2 
                the thesis becomes 
                d1:C
                  .u0:T
                    .i:nat
                      .H4:getl i c (CHead d1 (Bind Abbr) u0)
                        .c2:C.t2:T.H5:(fsubst0 i u0 c (THead (Bind Abst) u t) c2 t2).(arity g c2 t2 (AHead a1 a2))
                (H1) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i:nat
                         .getl i c (CHead d1 (Bind Abbr) u0)
                           c2:C.t2:T.(fsubst0 i u0 c u c2 t2)(arity g c2 t2 (asucc g a1))
                (H3) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i:nat
                         .getl i (CHead c (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                           c2:C.t2:T.(fsubst0 i u0 (CHead c (Bind Abst) u) t c2 t2)(arity g c2 t2 a2)
                    assume d1C
                    assume u0T
                    assume inat
                    suppose H4getl i c (CHead d1 (Bind Abbr) u0)
                    assume c2C
                    assume t2T
                    suppose H5fsubst0 i u0 c (THead (Bind Abst) u t) c2 t2
                      (H_x
                         by (fsubst0_gen_base . . . . . . H5)

                            or3
                              land (eq C c c2) (subst0 i u0 (THead (Bind Abst) u t) t2)
                              land (eq T (THead (Bind Abst) u t) t2) (csubst0 i u0 c c2)
                              land (subst0 i u0 (THead (Bind Abst) u t) t2) (csubst0 i u0 c c2)
                      end of H_x
                      (H6consider H_x
                      we proceed by induction on H6 to prove arity g c2 t2 (AHead a1 a2)
                         case or3_intro0 : H7:land (eq C c c2) (subst0 i u0 (THead (Bind Abst) u t) t2) 
                            the thesis becomes arity g c2 t2 (AHead a1 a2)
                               we proceed by induction on H7 to prove arity g c2 t2 (AHead a1 a2)
                                  case conj : H8:eq C c c2 H9:subst0 i u0 (THead (Bind Abst) u t) t2 
                                     the thesis becomes arity g c2 t2 (AHead a1 a2)
                                        we proceed by induction on H8 to prove arity g c2 t2 (AHead a1 a2)
                                           case refl_equal : 
                                              the thesis becomes arity g c t2 (AHead a1 a2)
                                                 by (subst0_gen_head . . . . . . H9)
                                                 we proved 
                                                    or3
                                                      ex2 T λu2:T.eq T t2 (THead (Bind Abst) u2 t) λu2:T.subst0 i u0 u u2
                                                      ex2 T λt2:T.eq T t2 (THead (Bind Abst) u t2) λt2:T.subst0 (s (Bind Abst) i) u0 t t2
                                                      ex3_2
                                                        T
                                                        T
                                                        λu2:T.λt2:T.eq T t2 (THead (Bind Abst) u2 t2)
                                                        λu2:T.λ:T.subst0 i u0 u u2
                                                        λ:T.λt2:T.subst0 (s (Bind Abst) i) u0 t t2
                                                 we proceed by induction on the previous result to prove arity g c t2 (AHead a1 a2)
                                                    case or3_intro0 : H10:ex2 T λu2:T.eq T t2 (THead (Bind Abst) u2 t) λu2:T.subst0 i u0 u u2 
                                                       the thesis becomes arity g c t2 (AHead a1 a2)
                                                          we proceed by induction on H10 to prove arity g c t2 (AHead a1 a2)
                                                             case ex_intro2 : x:T H11:eq T t2 (THead (Bind Abst) x t) H12:subst0 i u0 u x 
                                                                the thesis becomes arity g c t2 (AHead a1 a2)
                                                                   (h1
                                                                      by (fsubst0_snd . . . . . H12)
                                                                      we proved fsubst0 i u0 c u c x
                                                                      by (H1 . . . H4 . . previous)
arity g c x (asucc g a1)
                                                                   end of h1
                                                                   (h2
                                                                      (h1
                                                                         by (clear_bind . . .)
                                                                         we proved clear (CHead c (Bind Abst) u) (CHead c (Bind Abst) u)
                                                                         by (getl_clear_bind . . . . previous . . H4)
getl (S i) (CHead c (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                                      end of h1
                                                                      (h2
                                                                         by (csubst0_snd_bind . . . . . H12 .)
                                                                         we proved csubst0 (S i) u0 (CHead c (Bind Abst) u) (CHead c (Bind Abst) x)
                                                                         by (fsubst0_fst . . . . . previous)
fsubst0 (S i) u0 (CHead c (Bind Abst) u) t (CHead c (Bind Abst) x) t
                                                                      end of h2
                                                                      by (H3 . . . h1 . . h2)
arity g (CHead c (Bind Abst) x) t a2
                                                                   end of h2
                                                                   by (arity_head . . . . h1 . . h2)
                                                                   we proved arity g c (THead (Bind Abst) x t) (AHead a1 a2)
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 (AHead a1 a2)
arity g c t2 (AHead a1 a2)
                                                    case or3_intro1 : H10:ex2 T λt3:T.eq T t2 (THead (Bind Abst) u t3) λt3:T.subst0 (s (Bind Abst) i) u0 t t3 
                                                       the thesis becomes arity g c t2 (AHead a1 a2)
                                                          we proceed by induction on H10 to prove arity g c t2 (AHead a1 a2)
                                                             case ex_intro2 : x:T H11:eq T t2 (THead (Bind Abst) u x) H12:subst0 (s (Bind Abst) i) u0 t x 
                                                                the thesis becomes arity g c t2 (AHead a1 a2)
                                                                   (h1
                                                                      by (clear_bind . . .)
                                                                      we proved clear (CHead c (Bind Abst) u) (CHead c (Bind Abst) u)
                                                                      by (getl_clear_bind . . . . previous . . H4)
getl (S i) (CHead c (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                                   end of h1
                                                                   (h2
                                                                      consider H12
                                                                      we proved subst0 (s (Bind Abst) i) u0 t x
                                                                      that is equivalent to subst0 (S i) u0 t x
                                                                      by (fsubst0_snd . . . . . previous)
fsubst0 (S i) u0 (CHead c (Bind Abst) u) t (CHead c (Bind Abst) u) x
                                                                   end of h2
                                                                   by (H3 . . . h1 . . h2)
                                                                   we proved arity g (CHead c (Bind Abst) u) x a2
                                                                   by (arity_head . . . . H0 . . previous)
                                                                   we proved arity g c (THead (Bind Abst) u x) (AHead a1 a2)
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 (AHead a1 a2)
arity g c t2 (AHead a1 a2)
                                                    case or3_intro2 : H10:ex3_2 T T λu2:T.λt3:T.eq T t2 (THead (Bind Abst) u2 t3) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt3:T.subst0 (s (Bind Abst) i) u0 t t3 
                                                       the thesis becomes arity g c t2 (AHead a1 a2)
                                                          we proceed by induction on H10 to prove arity g c t2 (AHead a1 a2)
                                                             case ex3_2_intro : x0:T x1:T H11:eq T t2 (THead (Bind Abst) x0 x1) H12:subst0 i u0 u x0 H13:subst0 (s (Bind Abst) i) u0 t x1 
                                                                the thesis becomes arity g c t2 (AHead a1 a2)
                                                                   (h1
                                                                      by (fsubst0_snd . . . . . H12)
                                                                      we proved fsubst0 i u0 c u c x0
                                                                      by (H1 . . . H4 . . previous)
arity g c x0 (asucc g a1)
                                                                   end of h1
                                                                   (h2
                                                                      (h1
                                                                         by (clear_bind . . .)
                                                                         we proved clear (CHead c (Bind Abst) u) (CHead c (Bind Abst) u)
                                                                         by (getl_clear_bind . . . . previous . . H4)
getl (S i) (CHead c (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                                      end of h1
                                                                      (h2
                                                                         (h1
                                                                            consider H13
                                                                            we proved subst0 (s (Bind Abst) i) u0 t x1
subst0 (S i) u0 t x1
                                                                         end of h1
                                                                         (h2
                                                                            by (csubst0_snd_bind . . . . . H12 .)
csubst0 (S i) u0 (CHead c (Bind Abst) u) (CHead c (Bind Abst) x0)
                                                                         end of h2
                                                                         by (fsubst0_both . . . . . h1 . h2)
fsubst0 (S i) u0 (CHead c (Bind Abst) u) t (CHead c (Bind Abst) x0) x1
                                                                      end of h2
                                                                      by (H3 . . . h1 . . h2)
arity g (CHead c (Bind Abst) x0) x1 a2
                                                                   end of h2
                                                                   by (arity_head . . . . h1 . . h2)
                                                                   we proved arity g c (THead (Bind Abst) x0 x1) (AHead a1 a2)
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 (AHead a1 a2)
arity g c t2 (AHead a1 a2)
arity g c t2 (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
                         case or3_intro1 : H7:land (eq T (THead (Bind Abst) u t) t2) (csubst0 i u0 c c2) 
                            the thesis becomes arity g c2 t2 (AHead a1 a2)
                               we proceed by induction on H7 to prove arity g c2 t2 (AHead a1 a2)
                                  case conj : H8:eq T (THead (Bind Abst) u t) t2 H9:csubst0 i u0 c c2 
                                     the thesis becomes arity g c2 t2 (AHead a1 a2)
                                        we proceed by induction on H8 to prove arity g c2 t2 (AHead a1 a2)
                                           case refl_equal : 
                                              the thesis becomes arity g c2 (THead (Bind Abst) u t) (AHead a1 a2)
                                                 (h1
                                                    by (fsubst0_fst . . . . . H9)
                                                    we proved fsubst0 i u0 c u c2 u
                                                    by (H1 . . . H4 . . previous)
arity g c2 u (asucc g a1)
                                                 end of h1
                                                 (h2
                                                    (h1
                                                       by (clear_bind . . .)
                                                       we proved clear (CHead c (Bind Abst) u) (CHead c (Bind Abst) u)
                                                       by (getl_clear_bind . . . . previous . . H4)
getl (S i) (CHead c (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                    end of h1
                                                    (h2
                                                       by (csubst0_fst_bind . . . . . H9 .)
                                                       we proved csubst0 (S i) u0 (CHead c (Bind Abst) u) (CHead c2 (Bind Abst) u)
                                                       by (fsubst0_fst . . . . . previous)
fsubst0 (S i) u0 (CHead c (Bind Abst) u) t (CHead c2 (Bind Abst) u) t
                                                    end of h2
                                                    by (H3 . . . h1 . . h2)
arity g (CHead c2 (Bind Abst) u) t a2
                                                 end of h2
                                                 by (arity_head . . . . h1 . . h2)
arity g c2 (THead (Bind Abst) u t) (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
                         case or3_intro2 : H7:land (subst0 i u0 (THead (Bind Abst) u t) t2) (csubst0 i u0 c c2) 
                            the thesis becomes arity g c2 t2 (AHead a1 a2)
                               we proceed by induction on H7 to prove arity g c2 t2 (AHead a1 a2)
                                  case conj : H8:subst0 i u0 (THead (Bind Abst) u t) t2 H9:csubst0 i u0 c c2 
                                     the thesis becomes arity g c2 t2 (AHead a1 a2)
                                        by (subst0_gen_head . . . . . . H8)
                                        we proved 
                                           or3
                                             ex2 T λu2:T.eq T t2 (THead (Bind Abst) u2 t) λu2:T.subst0 i u0 u u2
                                             ex2 T λt2:T.eq T t2 (THead (Bind Abst) u t2) λt2:T.subst0 (s (Bind Abst) i) u0 t t2
                                             ex3_2
                                               T
                                               T
                                               λu2:T.λt2:T.eq T t2 (THead (Bind Abst) u2 t2)
                                               λu2:T.λ:T.subst0 i u0 u u2
                                               λ:T.λt2:T.subst0 (s (Bind Abst) i) u0 t t2
                                        we proceed by induction on the previous result to prove arity g c2 t2 (AHead a1 a2)
                                           case or3_intro0 : H10:ex2 T λu2:T.eq T t2 (THead (Bind Abst) u2 t) λu2:T.subst0 i u0 u u2 
                                              the thesis becomes arity g c2 t2 (AHead a1 a2)
                                                 we proceed by induction on H10 to prove arity g c2 t2 (AHead a1 a2)
                                                    case ex_intro2 : x:T H11:eq T t2 (THead (Bind Abst) x t) H12:subst0 i u0 u x 
                                                       the thesis becomes arity g c2 t2 (AHead a1 a2)
                                                          (h1
                                                             by (fsubst0_both . . . . . H12 . H9)
                                                             we proved fsubst0 i u0 c u c2 x
                                                             by (H1 . . . H4 . . previous)
arity g c2 x (asucc g a1)
                                                          end of h1
                                                          (h2
                                                             (h1
                                                                by (clear_bind . . .)
                                                                we proved clear (CHead c (Bind Abst) u) (CHead c (Bind Abst) u)
                                                                by (getl_clear_bind . . . . previous . . H4)
getl (S i) (CHead c (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                             end of h1
                                                             (h2
                                                                by (csubst0_both_bind . . . . . H12 . . H9)
                                                                we proved csubst0 (S i) u0 (CHead c (Bind Abst) u) (CHead c2 (Bind Abst) x)
                                                                by (fsubst0_fst . . . . . previous)
fsubst0 (S i) u0 (CHead c (Bind Abst) u) t (CHead c2 (Bind Abst) x) t
                                                             end of h2
                                                             by (H3 . . . h1 . . h2)
arity g (CHead c2 (Bind Abst) x) t a2
                                                          end of h2
                                                          by (arity_head . . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Bind Abst) x t) (AHead a1 a2)
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
                                           case or3_intro1 : H10:ex2 T λt3:T.eq T t2 (THead (Bind Abst) u t3) λt3:T.subst0 (s (Bind Abst) i) u0 t t3 
                                              the thesis becomes arity g c2 t2 (AHead a1 a2)
                                                 we proceed by induction on H10 to prove arity g c2 t2 (AHead a1 a2)
                                                    case ex_intro2 : x:T H11:eq T t2 (THead (Bind Abst) u x) H12:subst0 (s (Bind Abst) i) u0 t x 
                                                       the thesis becomes arity g c2 t2 (AHead a1 a2)
                                                          (h1
                                                             by (fsubst0_fst . . . . . H9)
                                                             we proved fsubst0 i u0 c u c2 u
                                                             by (H1 . . . H4 . . previous)
arity g c2 u (asucc g a1)
                                                          end of h1
                                                          (h2
                                                             (h1
                                                                by (clear_bind . . .)
                                                                we proved clear (CHead c (Bind Abst) u) (CHead c (Bind Abst) u)
                                                                by (getl_clear_bind . . . . previous . . H4)
getl (S i) (CHead c (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                             end of h1
                                                             (h2
                                                                (h1
                                                                   consider H12
                                                                   we proved subst0 (s (Bind Abst) i) u0 t x
subst0 (S i) u0 t x
                                                                end of h1
                                                                (h2
                                                                   by (csubst0_fst_bind . . . . . H9 .)
csubst0 (S i) u0 (CHead c (Bind Abst) u) (CHead c2 (Bind Abst) u)
                                                                end of h2
                                                                by (fsubst0_both . . . . . h1 . h2)
fsubst0 (S i) u0 (CHead c (Bind Abst) u) t (CHead c2 (Bind Abst) u) x
                                                             end of h2
                                                             by (H3 . . . h1 . . h2)
arity g (CHead c2 (Bind Abst) u) x a2
                                                          end of h2
                                                          by (arity_head . . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Bind Abst) u x) (AHead a1 a2)
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
                                           case or3_intro2 : H10:ex3_2 T T λu2:T.λt3:T.eq T t2 (THead (Bind Abst) u2 t3) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt3:T.subst0 (s (Bind Abst) i) u0 t t3 
                                              the thesis becomes arity g c2 t2 (AHead a1 a2)
                                                 we proceed by induction on H10 to prove arity g c2 t2 (AHead a1 a2)
                                                    case ex3_2_intro : x0:T x1:T H11:eq T t2 (THead (Bind Abst) x0 x1) H12:subst0 i u0 u x0 H13:subst0 (s (Bind Abst) i) u0 t x1 
                                                       the thesis becomes arity g c2 t2 (AHead a1 a2)
                                                          (h1
                                                             by (fsubst0_both . . . . . H12 . H9)
                                                             we proved fsubst0 i u0 c u c2 x0
                                                             by (H1 . . . H4 . . previous)
arity g c2 x0 (asucc g a1)
                                                          end of h1
                                                          (h2
                                                             (h1
                                                                by (clear_bind . . .)
                                                                we proved clear (CHead c (Bind Abst) u) (CHead c (Bind Abst) u)
                                                                by (getl_clear_bind . . . . previous . . H4)
getl (S i) (CHead c (Bind Abst) u) (CHead d1 (Bind Abbr) u0)
                                                             end of h1
                                                             (h2
                                                                (h1
                                                                   consider H13
                                                                   we proved subst0 (s (Bind Abst) i) u0 t x1
subst0 (S i) u0 t x1
                                                                end of h1
                                                                (h2
                                                                   by (csubst0_both_bind . . . . . H12 . . H9)
csubst0 (S i) u0 (CHead c (Bind Abst) u) (CHead c2 (Bind Abst) x0)
                                                                end of h2
                                                                by (fsubst0_both . . . . . h1 . h2)
fsubst0 (S i) u0 (CHead c (Bind Abst) u) t (CHead c2 (Bind Abst) x0) x1
                                                             end of h2
                                                             by (H3 . . . h1 . . h2)
arity g (CHead c2 (Bind Abst) x0) x1 a2
                                                          end of h2
                                                          by (arity_head . . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Bind Abst) x0 x1) (AHead a1 a2)
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
arity g c2 t2 (AHead a1 a2)
                      we proved arity g c2 t2 (AHead a1 a2)

                      d1:C
                        .u0:T
                          .i:nat
                            .H4:getl i c (CHead d1 (Bind Abbr) u0)
                              .c2:C.t2:T.H5:(fsubst0 i u0 c (THead (Bind Abst) u t) c2 t2).(arity g c2 t2 (AHead a1 a2))
             case arity_appl : c:C u:T a1:A H0:arity g c u a1 t:T a2:A H2:arity g c t (AHead a1 a2) 
                the thesis becomes 
                d1:C
                  .u0:T
                    .i:nat
                      .H4:getl i c (CHead d1 (Bind Abbr) u0)
                        .c2:C.t2:T.H5:(fsubst0 i u0 c (THead (Flat Appl) u t) c2 t2).(arity g c2 t2 a2)
                (H1) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i:nat
                         .(getl i c (CHead d1 (Bind Abbr) u0))c2:C.t2:T.(fsubst0 i u0 c u c2 t2)(arity g c2 t2 a1)
                (H3) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i:nat
                         .getl i c (CHead d1 (Bind Abbr) u0)
                           c2:C.t2:T.(fsubst0 i u0 c t c2 t2)(arity g c2 t2 (AHead a1 a2))
                    assume d1C
                    assume u0T
                    assume inat
                    suppose H4getl i c (CHead d1 (Bind Abbr) u0)
                    assume c2C
                    assume t2T
                    suppose H5fsubst0 i u0 c (THead (Flat Appl) u t) c2 t2
                      (H_x
                         by (fsubst0_gen_base . . . . . . H5)

                            or3
                              land (eq C c c2) (subst0 i u0 (THead (Flat Appl) u t) t2)
                              land (eq T (THead (Flat Appl) u t) t2) (csubst0 i u0 c c2)
                              land (subst0 i u0 (THead (Flat Appl) u t) t2) (csubst0 i u0 c c2)
                      end of H_x
                      (H6consider H_x
                      we proceed by induction on H6 to prove arity g c2 t2 a2
                         case or3_intro0 : H7:land (eq C c c2) (subst0 i u0 (THead (Flat Appl) u t) t2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H7 to prove arity g c2 t2 a2
                                  case conj : H8:eq C c c2 H9:subst0 i u0 (THead (Flat Appl) u t) t2 
                                     the thesis becomes arity g c2 t2 a2
                                        we proceed by induction on H8 to prove arity g c2 t2 a2
                                           case refl_equal : 
                                              the thesis becomes arity g c t2 a2
                                                 by (subst0_gen_head . . . . . . H9)
                                                 we proved 
                                                    or3
                                                      ex2 T λu2:T.eq T t2 (THead (Flat Appl) u2 t) λu2:T.subst0 i u0 u u2
                                                      ex2 T λt2:T.eq T t2 (THead (Flat Appl) u t2) λt2:T.subst0 (s (Flat Appl) i) u0 t t2
                                                      ex3_2
                                                        T
                                                        T
                                                        λu2:T.λt2:T.eq T t2 (THead (Flat Appl) u2 t2)
                                                        λu2:T.λ:T.subst0 i u0 u u2
                                                        λ:T.λt2:T.subst0 (s (Flat Appl) i) u0 t t2
                                                 we proceed by induction on the previous result to prove arity g c t2 a2
                                                    case or3_intro0 : H10:ex2 T λu2:T.eq T t2 (THead (Flat Appl) u2 t) λu2:T.subst0 i u0 u u2 
                                                       the thesis becomes arity g c t2 a2
                                                          we proceed by induction on H10 to prove arity g c t2 a2
                                                             case ex_intro2 : x:T H11:eq T t2 (THead (Flat Appl) x t) H12:subst0 i u0 u x 
                                                                the thesis becomes arity g c t2 a2
                                                                   by (fsubst0_snd . . . . . H12)
                                                                   we proved fsubst0 i u0 c u c x
                                                                   by (H1 . . . H4 . . previous)
                                                                   we proved arity g c x a1
                                                                   by (arity_appl . . . . previous . . H2)
                                                                   we proved arity g c (THead (Flat Appl) x t) a2
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 a2
arity g c t2 a2
                                                    case or3_intro1 : H10:ex2 T λt3:T.eq T t2 (THead (Flat Appl) u t3) λt3:T.subst0 (s (Flat Appl) i) u0 t t3 
                                                       the thesis becomes arity g c t2 a2
                                                          we proceed by induction on H10 to prove arity g c t2 a2
                                                             case ex_intro2 : x:T H11:eq T t2 (THead (Flat Appl) u x) H12:subst0 (s (Flat Appl) i) u0 t x 
                                                                the thesis becomes arity g c t2 a2
                                                                   consider H12
                                                                   we proved subst0 (s (Flat Appl) i) u0 t x
                                                                   that is equivalent to subst0 i u0 t x
                                                                   by (fsubst0_snd . . . . . previous)
                                                                   we proved fsubst0 i u0 c t c x
                                                                   by (H3 . . . H4 . . previous)
                                                                   we proved arity g c x (AHead a1 a2)
                                                                   by (arity_appl . . . . H0 . . previous)
                                                                   we proved arity g c (THead (Flat Appl) u x) a2
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 a2
arity g c t2 a2
                                                    case or3_intro2 : H10:ex3_2 T T λu2:T.λt3:T.eq T t2 (THead (Flat Appl) u2 t3) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt3:T.subst0 (s (Flat Appl) i) u0 t t3 
                                                       the thesis becomes arity g c t2 a2
                                                          we proceed by induction on H10 to prove arity g c t2 a2
                                                             case ex3_2_intro : x0:T x1:T H11:eq T t2 (THead (Flat Appl) x0 x1) H12:subst0 i u0 u x0 H13:subst0 (s (Flat Appl) i) u0 t x1 
                                                                the thesis becomes arity g c t2 a2
                                                                   (h1
                                                                      by (fsubst0_snd . . . . . H12)
                                                                      we proved fsubst0 i u0 c u c x0
                                                                      by (H1 . . . H4 . . previous)
arity g c x0 a1
                                                                   end of h1
                                                                   (h2
                                                                      consider H13
                                                                      we proved subst0 (s (Flat Appl) i) u0 t x1
                                                                      that is equivalent to subst0 i u0 t x1
                                                                      by (fsubst0_snd . . . . . previous)
                                                                      we proved fsubst0 i u0 c t c x1
                                                                      by (H3 . . . H4 . . previous)
arity g c x1 (AHead a1 a2)
                                                                   end of h2
                                                                   by (arity_appl . . . . h1 . . h2)
                                                                   we proved arity g c (THead (Flat Appl) x0 x1) a2
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 a2
arity g c t2 a2
arity g c t2 a2
arity g c2 t2 a2
arity g c2 t2 a2
                         case or3_intro1 : H7:land (eq T (THead (Flat Appl) u t) t2) (csubst0 i u0 c c2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H7 to prove arity g c2 t2 a2
                                  case conj : H8:eq T (THead (Flat Appl) u t) t2 H9:csubst0 i u0 c c2 
                                     the thesis becomes arity g c2 t2 a2
                                        we proceed by induction on H8 to prove arity g c2 t2 a2
                                           case refl_equal : 
                                              the thesis becomes arity g c2 (THead (Flat Appl) u t) a2
                                                 (h1
                                                    by (fsubst0_fst . . . . . H9)
                                                    we proved fsubst0 i u0 c u c2 u
                                                    by (H1 . . . H4 . . previous)
arity g c2 u a1
                                                 end of h1
                                                 (h2
                                                    by (fsubst0_fst . . . . . H9)
                                                    we proved fsubst0 i u0 c t c2 t
                                                    by (H3 . . . H4 . . previous)
arity g c2 t (AHead a1 a2)
                                                 end of h2
                                                 by (arity_appl . . . . h1 . . h2)
arity g c2 (THead (Flat Appl) u t) a2
arity g c2 t2 a2
arity g c2 t2 a2
                         case or3_intro2 : H7:land (subst0 i u0 (THead (Flat Appl) u t) t2) (csubst0 i u0 c c2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H7 to prove arity g c2 t2 a2
                                  case conj : H8:subst0 i u0 (THead (Flat Appl) u t) t2 H9:csubst0 i u0 c c2 
                                     the thesis becomes arity g c2 t2 a2
                                        by (subst0_gen_head . . . . . . H8)
                                        we proved 
                                           or3
                                             ex2 T λu2:T.eq T t2 (THead (Flat Appl) u2 t) λu2:T.subst0 i u0 u u2
                                             ex2 T λt2:T.eq T t2 (THead (Flat Appl) u t2) λt2:T.subst0 (s (Flat Appl) i) u0 t t2
                                             ex3_2
                                               T
                                               T
                                               λu2:T.λt2:T.eq T t2 (THead (Flat Appl) u2 t2)
                                               λu2:T.λ:T.subst0 i u0 u u2
                                               λ:T.λt2:T.subst0 (s (Flat Appl) i) u0 t t2
                                        we proceed by induction on the previous result to prove arity g c2 t2 a2
                                           case or3_intro0 : H10:ex2 T λu2:T.eq T t2 (THead (Flat Appl) u2 t) λu2:T.subst0 i u0 u u2 
                                              the thesis becomes arity g c2 t2 a2
                                                 we proceed by induction on H10 to prove arity g c2 t2 a2
                                                    case ex_intro2 : x:T H11:eq T t2 (THead (Flat Appl) x t) H12:subst0 i u0 u x 
                                                       the thesis becomes arity g c2 t2 a2
                                                          (h1
                                                             by (fsubst0_both . . . . . H12 . H9)
                                                             we proved fsubst0 i u0 c u c2 x
                                                             by (H1 . . . H4 . . previous)
arity g c2 x a1
                                                          end of h1
                                                          (h2
                                                             by (fsubst0_fst . . . . . H9)
                                                             we proved fsubst0 i u0 c t c2 t
                                                             by (H3 . . . H4 . . previous)
arity g c2 t (AHead a1 a2)
                                                          end of h2
                                                          by (arity_appl . . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Flat Appl) x t) a2
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 a2
arity g c2 t2 a2
                                           case or3_intro1 : H10:ex2 T λt3:T.eq T t2 (THead (Flat Appl) u t3) λt3:T.subst0 (s (Flat Appl) i) u0 t t3 
                                              the thesis becomes arity g c2 t2 a2
                                                 we proceed by induction on H10 to prove arity g c2 t2 a2
                                                    case ex_intro2 : x:T H11:eq T t2 (THead (Flat Appl) u x) H12:subst0 (s (Flat Appl) i) u0 t x 
                                                       the thesis becomes arity g c2 t2 a2
                                                          (h1
                                                             by (fsubst0_fst . . . . . H9)
                                                             we proved fsubst0 i u0 c u c2 u
                                                             by (H1 . . . H4 . . previous)
arity g c2 u a1
                                                          end of h1
                                                          (h2
                                                             consider H12
                                                             we proved subst0 (s (Flat Appl) i) u0 t x
                                                             that is equivalent to subst0 i u0 t x
                                                             by (fsubst0_both . . . . . previous . H9)
                                                             we proved fsubst0 i u0 c t c2 x
                                                             by (H3 . . . H4 . . previous)
arity g c2 x (AHead a1 a2)
                                                          end of h2
                                                          by (arity_appl . . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Flat Appl) u x) a2
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 a2
arity g c2 t2 a2
                                           case or3_intro2 : H10:ex3_2 T T λu2:T.λt3:T.eq T t2 (THead (Flat Appl) u2 t3) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt3:T.subst0 (s (Flat Appl) i) u0 t t3 
                                              the thesis becomes arity g c2 t2 a2
                                                 we proceed by induction on H10 to prove arity g c2 t2 a2
                                                    case ex3_2_intro : x0:T x1:T H11:eq T t2 (THead (Flat Appl) x0 x1) H12:subst0 i u0 u x0 H13:subst0 (s (Flat Appl) i) u0 t x1 
                                                       the thesis becomes arity g c2 t2 a2
                                                          (h1
                                                             by (fsubst0_both . . . . . H12 . H9)
                                                             we proved fsubst0 i u0 c u c2 x0
                                                             by (H1 . . . H4 . . previous)
arity g c2 x0 a1
                                                          end of h1
                                                          (h2
                                                             consider H13
                                                             we proved subst0 (s (Flat Appl) i) u0 t x1
                                                             that is equivalent to subst0 i u0 t x1
                                                             by (fsubst0_both . . . . . previous . H9)
                                                             we proved fsubst0 i u0 c t c2 x1
                                                             by (H3 . . . H4 . . previous)
arity g c2 x1 (AHead a1 a2)
                                                          end of h2
                                                          by (arity_appl . . . . h1 . . h2)
                                                          we proved arity g c2 (THead (Flat Appl) x0 x1) a2
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 a2
arity g c2 t2 a2
arity g c2 t2 a2
arity g c2 t2 a2
                      we proved arity g c2 t2 a2

                      d1:C
                        .u0:T
                          .i:nat
                            .H4:getl i c (CHead d1 (Bind Abbr) u0)
                              .c2:C.t2:T.H5:(fsubst0 i u0 c (THead (Flat Appl) u t) c2 t2).(arity g c2 t2 a2)
             case arity_cast : c:C u:T a0:A H0:arity g c u (asucc g a0) t:T H2:arity g c t a0 
                the thesis becomes 
                d1:C
                  .u0:T
                    .i:nat
                      .H4:getl i c (CHead d1 (Bind Abbr) u0)
                        .c2:C.t2:T.H5:(fsubst0 i u0 c (THead (Flat Cast) u t) c2 t2).(arity g c2 t2 a0)
                (H1) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i:nat
                         .getl i c (CHead d1 (Bind Abbr) u0)
                           c2:C.t2:T.(fsubst0 i u0 c u c2 t2)(arity g c2 t2 (asucc g a0))
                (H3) by induction hypothesis we know 
                   d1:C
                     .u0:T
                       .i:nat
                         .(getl i c (CHead d1 (Bind Abbr) u0))c2:C.t2:T.(fsubst0 i u0 c t c2 t2)(arity g c2 t2 a0)
                    assume d1C
                    assume u0T
                    assume inat
                    suppose H4getl i c (CHead d1 (Bind Abbr) u0)
                    assume c2C
                    assume t2T
                    suppose H5fsubst0 i u0 c (THead (Flat Cast) u t) c2 t2
                      (H_x
                         by (fsubst0_gen_base . . . . . . H5)

                            or3
                              land (eq C c c2) (subst0 i u0 (THead (Flat Cast) u t) t2)
                              land (eq T (THead (Flat Cast) u t) t2) (csubst0 i u0 c c2)
                              land (subst0 i u0 (THead (Flat Cast) u t) t2) (csubst0 i u0 c c2)
                      end of H_x
                      (H6consider H_x
                      we proceed by induction on H6 to prove arity g c2 t2 a0
                         case or3_intro0 : H7:land (eq C c c2) (subst0 i u0 (THead (Flat Cast) u t) t2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H7 to prove arity g c2 t2 a0
                                  case conj : H8:eq C c c2 H9:subst0 i u0 (THead (Flat Cast) u t) t2 
                                     the thesis becomes arity g c2 t2 a0
                                        we proceed by induction on H8 to prove arity g c2 t2 a0
                                           case refl_equal : 
                                              the thesis becomes arity g c t2 a0
                                                 by (subst0_gen_head . . . . . . H9)
                                                 we proved 
                                                    or3
                                                      ex2 T λu2:T.eq T t2 (THead (Flat Cast) u2 t) λu2:T.subst0 i u0 u u2
                                                      ex2 T λt2:T.eq T t2 (THead (Flat Cast) u t2) λt2:T.subst0 (s (Flat Cast) i) u0 t t2
                                                      ex3_2
                                                        T
                                                        T
                                                        λu2:T.λt2:T.eq T t2 (THead (Flat Cast) u2 t2)
                                                        λu2:T.λ:T.subst0 i u0 u u2
                                                        λ:T.λt2:T.subst0 (s (Flat Cast) i) u0 t t2
                                                 we proceed by induction on the previous result to prove arity g c t2 a0
                                                    case or3_intro0 : H10:ex2 T λu2:T.eq T t2 (THead (Flat Cast) u2 t) λu2:T.subst0 i u0 u u2 
                                                       the thesis becomes arity g c t2 a0
                                                          we proceed by induction on H10 to prove arity g c t2 a0
                                                             case ex_intro2 : x:T H11:eq T t2 (THead (Flat Cast) x t) H12:subst0 i u0 u x 
                                                                the thesis becomes arity g c t2 a0
                                                                   by (fsubst0_snd . . . . . H12)
                                                                   we proved fsubst0 i u0 c u c x
                                                                   by (H1 . . . H4 . . previous)
                                                                   we proved arity g c x (asucc g a0)
                                                                   by (arity_cast . . . . previous . H2)
                                                                   we proved arity g c (THead (Flat Cast) x t) a0
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 a0
arity g c t2 a0
                                                    case or3_intro1 : H10:ex2 T λt3:T.eq T t2 (THead (Flat Cast) u t3) λt3:T.subst0 (s (Flat Cast) i) u0 t t3 
                                                       the thesis becomes arity g c t2 a0
                                                          we proceed by induction on H10 to prove arity g c t2 a0
                                                             case ex_intro2 : x:T H11:eq T t2 (THead (Flat Cast) u x) H12:subst0 (s (Flat Cast) i) u0 t x 
                                                                the thesis becomes arity g c t2 a0
                                                                   consider H12
                                                                   we proved subst0 (s (Flat Cast) i) u0 t x
                                                                   that is equivalent to subst0 i u0 t x
                                                                   by (fsubst0_snd . . . . . previous)
                                                                   we proved fsubst0 i u0 c t c x
                                                                   by (H3 . . . H4 . . previous)
                                                                   we proved arity g c x a0
                                                                   by (arity_cast . . . . H0 . previous)
                                                                   we proved arity g c (THead (Flat Cast) u x) a0
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 a0
arity g c t2 a0
                                                    case or3_intro2 : H10:ex3_2 T T λu2:T.λt3:T.eq T t2 (THead (Flat Cast) u2 t3) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt3:T.subst0 (s (Flat Cast) i) u0 t t3 
                                                       the thesis becomes arity g c t2 a0
                                                          we proceed by induction on H10 to prove arity g c t2 a0
                                                             case ex3_2_intro : x0:T x1:T H11:eq T t2 (THead (Flat Cast) x0 x1) H12:subst0 i u0 u x0 H13:subst0 (s (Flat Cast) i) u0 t x1 
                                                                the thesis becomes arity g c t2 a0
                                                                   (h1
                                                                      by (fsubst0_snd . . . . . H12)
                                                                      we proved fsubst0 i u0 c u c x0
                                                                      by (H1 . . . H4 . . previous)
arity g c x0 (asucc g a0)
                                                                   end of h1
                                                                   (h2
                                                                      consider H13
                                                                      we proved subst0 (s (Flat Cast) i) u0 t x1
                                                                      that is equivalent to subst0 i u0 t x1
                                                                      by (fsubst0_snd . . . . . previous)
                                                                      we proved fsubst0 i u0 c t c x1
                                                                      by (H3 . . . H4 . . previous)
arity g c x1 a0
                                                                   end of h2
                                                                   by (arity_cast . . . . h1 . h2)
                                                                   we proved arity g c (THead (Flat Cast) x0 x1) a0
                                                                   by (eq_ind_r . . . previous . H11)
arity g c t2 a0
arity g c t2 a0
arity g c t2 a0
arity g c2 t2 a0
arity g c2 t2 a0
                         case or3_intro1 : H7:land (eq T (THead (Flat Cast) u t) t2) (csubst0 i u0 c c2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H7 to prove arity g c2 t2 a0
                                  case conj : H8:eq T (THead (Flat Cast) u t) t2 H9:csubst0 i u0 c c2 
                                     the thesis becomes arity g c2 t2 a0
                                        we proceed by induction on H8 to prove arity g c2 t2 a0
                                           case refl_equal : 
                                              the thesis becomes arity g c2 (THead (Flat Cast) u t) a0
                                                 (h1
                                                    by (fsubst0_fst . . . . . H9)
                                                    we proved fsubst0 i u0 c u c2 u
                                                    by (H1 . . . H4 . . previous)
arity g c2 u (asucc g a0)
                                                 end of h1
                                                 (h2
                                                    by (fsubst0_fst . . . . . H9)
                                                    we proved fsubst0 i u0 c t c2 t
                                                    by (H3 . . . H4 . . previous)
arity g c2 t a0
                                                 end of h2
                                                 by (arity_cast . . . . h1 . h2)
arity g c2 (THead (Flat Cast) u t) a0
arity g c2 t2 a0
arity g c2 t2 a0
                         case or3_intro2 : H7:land (subst0 i u0 (THead (Flat Cast) u t) t2) (csubst0 i u0 c c2) 
                            the thesis becomes arity g c2 t2 a0
                               we proceed by induction on H7 to prove arity g c2 t2 a0
                                  case conj : H8:subst0 i u0 (THead (Flat Cast) u t) t2 H9:csubst0 i u0 c c2 
                                     the thesis becomes arity g c2 t2 a0
                                        by (subst0_gen_head . . . . . . H8)
                                        we proved 
                                           or3
                                             ex2 T λu2:T.eq T t2 (THead (Flat Cast) u2 t) λu2:T.subst0 i u0 u u2
                                             ex2 T λt2:T.eq T t2 (THead (Flat Cast) u t2) λt2:T.subst0 (s (Flat Cast) i) u0 t t2
                                             ex3_2
                                               T
                                               T
                                               λu2:T.λt2:T.eq T t2 (THead (Flat Cast) u2 t2)
                                               λu2:T.λ:T.subst0 i u0 u u2
                                               λ:T.λt2:T.subst0 (s (Flat Cast) i) u0 t t2
                                        we proceed by induction on the previous result to prove arity g c2 t2 a0
                                           case or3_intro0 : H10:ex2 T λu2:T.eq T t2 (THead (Flat Cast) u2 t) λu2:T.subst0 i u0 u u2 
                                              the thesis becomes arity g c2 t2 a0
                                                 we proceed by induction on H10 to prove arity g c2 t2 a0
                                                    case ex_intro2 : x:T H11:eq T t2 (THead (Flat Cast) x t) H12:subst0 i u0 u x 
                                                       the thesis becomes arity g c2 t2 a0
                                                          (h1
                                                             by (fsubst0_both . . . . . H12 . H9)
                                                             we proved fsubst0 i u0 c u c2 x
                                                             by (H1 . . . H4 . . previous)
arity g c2 x (asucc g a0)
                                                          end of h1
                                                          (h2
                                                             by (fsubst0_fst . . . . . H9)
                                                             we proved fsubst0 i u0 c t c2 t
                                                             by (H3 . . . H4 . . previous)
arity g c2 t a0
                                                          end of h2
                                                          by (arity_cast . . . . h1 . h2)
                                                          we proved arity g c2 (THead (Flat Cast) x t) a0
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 a0
arity g c2 t2 a0
                                           case or3_intro1 : H10:ex2 T λt3:T.eq T t2 (THead (Flat Cast) u t3) λt3:T.subst0 (s (Flat Cast) i) u0 t t3 
                                              the thesis becomes arity g c2 t2 a0
                                                 we proceed by induction on H10 to prove arity g c2 t2 a0
                                                    case ex_intro2 : x:T H11:eq T t2 (THead (Flat Cast) u x) H12:subst0 (s (Flat Cast) i) u0 t x 
                                                       the thesis becomes arity g c2 t2 a0
                                                          (h1
                                                             by (fsubst0_fst . . . . . H9)
                                                             we proved fsubst0 i u0 c u c2 u
                                                             by (H1 . . . H4 . . previous)
arity g c2 u (asucc g a0)
                                                          end of h1
                                                          (h2
                                                             consider H12
                                                             we proved subst0 (s (Flat Cast) i) u0 t x
                                                             that is equivalent to subst0 i u0 t x
                                                             by (fsubst0_both . . . . . previous . H9)
                                                             we proved fsubst0 i u0 c t c2 x
                                                             by (H3 . . . H4 . . previous)
arity g c2 x a0
                                                          end of h2
                                                          by (arity_cast . . . . h1 . h2)
                                                          we proved arity g c2 (THead (Flat Cast) u x) a0
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 a0
arity g c2 t2 a0
                                           case or3_intro2 : H10:ex3_2 T T λu2:T.λt3:T.eq T t2 (THead (Flat Cast) u2 t3) λu2:T.λ:T.subst0 i u0 u u2 λ:T.λt3:T.subst0 (s (Flat Cast) i) u0 t t3 
                                              the thesis becomes arity g c2 t2 a0
                                                 we proceed by induction on H10 to prove arity g c2 t2 a0
                                                    case ex3_2_intro : x0:T x1:T H11:eq T t2 (THead (Flat Cast) x0 x1) H12:subst0 i u0 u x0 H13:subst0 (s (Flat Cast) i) u0 t x1 
                                                       the thesis becomes arity g c2 t2 a0
                                                          (h1
                                                             by (fsubst0_both . . . . . H12 . H9)
                                                             we proved fsubst0 i u0 c u c2 x0
                                                             by (H1 . . . H4 . . previous)
arity g c2 x0 (asucc g a0)
                                                          end of h1
                                                          (h2
                                                             consider H13
                                                             we proved subst0 (s (Flat Cast) i) u0 t x1
                                                             that is equivalent to subst0 i u0 t x1
                                                             by (fsubst0_both . . . . . previous . H9)
                                                             we proved fsubst0 i u0 c t c2 x1
                                                             by (H3 . . . H4 . . previous)
arity g c2 x1 a0
                                                          end of h2
                                                          by (arity_cast . . . . h1 . h2)
                                                          we proved arity g c2 (THead (Flat Cast) x0 x1) a0
                                                          by (eq_ind_r . . . previous . H11)
arity g c2 t2 a0
arity g c2 t2 a0
arity g c2 t2 a0
arity g c2 t2 a0
                      we proved arity g c2 t2 a0

                      d1:C
                        .u0:T
                          .i:nat
                            .H4:getl i c (CHead d1 (Bind Abbr) u0)
                              .c2:C.t2:T.H5:(fsubst0 i u0 c (THead (Flat Cast) u t) c2 t2).(arity g c2 t2 a0)
             case arity_repl : c:C t:T a1:A :arity g c t a1 a2:A H2:leq g a1 a2 
                the thesis becomes d1:C.u:T.i:nat.H3:(getl i c (CHead d1 (Bind Abbr) u)).c2:C.t2:T.H4:(fsubst0 i u c t c2 t2).(arity g c2 t2 a2)
                (H1) by induction hypothesis we know 
                   d1:C
                     .u:T
                       .i:nat
                         .getl i c (CHead d1 (Bind Abbr) u)
                           c2:C.t2:T.(fsubst0 i u c t c2 t2)(arity g c2 t2 a1)
                    assume d1C
                    assume uT
                    assume inat
                    suppose H3getl i c (CHead d1 (Bind Abbr) u)
                    assume c2C
                    assume t2T
                    suppose H4fsubst0 i u c t c2 t2
                      (H_x
                         by (fsubst0_gen_base . . . . . . H4)

                            or3
                              land (eq C c c2) (subst0 i u t t2)
                              land (eq T t t2) (csubst0 i u c c2)
                              land (subst0 i u t t2) (csubst0 i u c c2)
                      end of H_x
                      (H5consider H_x
                      we proceed by induction on H5 to prove arity g c2 t2 a2
                         case or3_intro0 : H6:land (eq C c c2) (subst0 i u t t2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H6 to prove arity g c2 t2 a2
                                  case conj : H7:eq C c c2 H8:subst0 i u t t2 
                                     the thesis becomes arity g c2 t2 a2
                                        we proceed by induction on H7 to prove arity g c2 t2 a2
                                           case refl_equal : 
                                              the thesis becomes arity g c t2 a2
                                                 by (fsubst0_snd . . . . . H8)
                                                 we proved fsubst0 i u c t c t2
                                                 by (H1 . . . H3 . . previous)
                                                 we proved arity g c t2 a1
                                                 by (arity_repl . . . . previous . H2)
arity g c t2 a2
arity g c2 t2 a2
arity g c2 t2 a2
                         case or3_intro1 : H6:land (eq T t t2) (csubst0 i u c c2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H6 to prove arity g c2 t2 a2
                                  case conj : H7:eq T t t2 H8:csubst0 i u c c2 
                                     the thesis becomes arity g c2 t2 a2
                                        we proceed by induction on H7 to prove arity g c2 t2 a2
                                           case refl_equal : 
                                              the thesis becomes arity g c2 t a2
                                                 by (fsubst0_fst . . . . . H8)
                                                 we proved fsubst0 i u c t c2 t
                                                 by (H1 . . . H3 . . previous)
                                                 we proved arity g c2 t a1
                                                 by (arity_repl . . . . previous . H2)
arity g c2 t a2
arity g c2 t2 a2
arity g c2 t2 a2
                         case or3_intro2 : H6:land (subst0 i u t t2) (csubst0 i u c c2) 
                            the thesis becomes arity g c2 t2 a2
                               we proceed by induction on H6 to prove arity g c2 t2 a2
                                  case conj : H7:subst0 i u t t2 H8:csubst0 i u c c2 
                                     the thesis becomes arity g c2 t2 a2
                                        by (fsubst0_both . . . . . H7 . H8)
                                        we proved fsubst0 i u c t c2 t2
                                        by (H1 . . . H3 . . previous)
                                        we proved arity g c2 t2 a1
                                        by (arity_repl . . . . previous . H2)
arity g c2 t2 a2
arity g c2 t2 a2
                      we proved arity g c2 t2 a2
d1:C.u:T.i:nat.H3:(getl i c (CHead d1 (Bind Abbr) u)).c2:C.t2:T.H4:(fsubst0 i u c t c2 t2).(arity g c2 t2 a2)
          we proved 
             d1:C
               .u:T
                 .i:nat
                   .(getl i c1 (CHead d1 (Bind Abbr) u))c2:C.t2:T.(fsubst0 i u c1 t1 c2 t2)(arity g c2 t2 a)
       we proved 
          g:G
            .c1:C
              .t1:T
                .a:A
                  .arity g c1 t1 a
                    d1:C
                         .u:T
                           .i:nat
                             .(getl i c1 (CHead d1 (Bind Abbr) u))c2:C.t2:T.(fsubst0 i u c1 t1 c2 t2)(arity g c2 t2 a)