-i c1 (CHead e1 (Bind b) v))).(let H1 \def (match H in drop1 return (\lambda
-(p: PList).(\lambda (c: C).(\lambda (c0: C).(\lambda (_: (drop1 p c c0)).((eq
-PList p PNil) \to ((eq C c c2) \to ((eq C c0 c1) \to (ex2 C (\lambda (e2:
-C).(drop1 PNil e2 e1)) (\lambda (e2: C).(getl i c2 (CHead e2 (Bind b)
-v))))))))))) with [(drop1_nil c) \Rightarrow (\lambda (_: (eq PList PNil
-PNil)).(\lambda (H2: (eq C c c2)).(\lambda (H3: (eq C c c1)).(eq_ind C c2
-(\lambda (c0: C).((eq C c0 c1) \to (ex2 C (\lambda (e2: C).(drop1 PNil e2
-e1)) (\lambda (e2: C).(getl i c2 (CHead e2 (Bind b) v)))))) (\lambda (H4: (eq
-C c2 c1)).(eq_ind C c1 (\lambda (c0: C).(ex2 C (\lambda (e2: C).(drop1 PNil
-e2 e1)) (\lambda (e2: C).(getl i c0 (CHead e2 (Bind b) v))))) (ex_intro2 C
-(\lambda (e2: C).(drop1 PNil e2 e1)) (\lambda (e2: C).(getl i c1 (CHead e2
-(Bind b) v))) e1 (drop1_nil e1) H0) c2 (sym_eq C c2 c1 H4))) c (sym_eq C c c2
-H2) H3)))) | (drop1_cons c0 c3 h d H1 c4 hds0 H2) \Rightarrow (\lambda (H3:
-(eq PList (PCons h d hds0) PNil)).(\lambda (H4: (eq C c0 c2)).(\lambda (H5:
-(eq C c4 c1)).((let H6 \def (eq_ind PList (PCons h d hds0) (\lambda (e:
-PList).(match e in PList return (\lambda (_: PList).Prop) with [PNil
-\Rightarrow False | (PCons _ _ _) \Rightarrow True])) I PNil H3) in
-(False_ind ((eq C c0 c2) \to ((eq C c4 c1) \to ((drop h d c0 c3) \to ((drop1
-hds0 c3 c4) \to (ex2 C (\lambda (e2: C).(drop1 PNil e2 e1)) (\lambda (e2:
-C).(getl i c2 (CHead e2 (Bind b) v)))))))) H6)) H4 H5 H1 H2))))]) in (H1
-(refl_equal PList PNil) (refl_equal C c2) (refl_equal C c1)))))))))))
-(\lambda (h: nat).(\lambda (d: nat).(\lambda (hds0: PList).(\lambda (H:
-((\forall (c1: C).(\forall (c2: C).((drop1 hds0 c2 c1) \to (\forall (b:
-B).(\forall (e1: C).(\forall (v: T).(\forall (i: nat).((getl i c1 (CHead e1
-(Bind b) v)) \to (ex2 C (\lambda (e2: C).(drop1 (ptrans hds0 i) e2 e1))
-(\lambda (e2: C).(getl (trans hds0 i) c2 (CHead e2 (Bind b) (lift1 (ptrans
-hds0 i) v))))))))))))))).(\lambda (c1: C).(\lambda (c2: C).(\lambda (H0:
-(drop1 (PCons h d hds0) c2 c1)).(\lambda (b: B).(\lambda (e1: C).(\lambda (v:
-T).(\lambda (i: nat).(\lambda (H1: (getl i c1 (CHead e1 (Bind b) v))).(let H2
-\def (match H0 in drop1 return (\lambda (p: PList).(\lambda (c: C).(\lambda
-(c0: C).(\lambda (_: (drop1 p c c0)).((eq PList p (PCons h d hds0)) \to ((eq
-C c c2) \to ((eq C c0 c1) \to (ex2 C (\lambda (e2: C).(drop1 (match (blt
-(trans hds0 i) d) with [true \Rightarrow (PCons h (minus d (S (trans hds0
-i))) (ptrans hds0 i)) | false \Rightarrow (ptrans hds0 i)]) e2 e1)) (\lambda
-(e2: C).(getl (match (blt (trans hds0 i) d) with [true \Rightarrow (trans
-hds0 i) | false \Rightarrow (plus (trans hds0 i) h)]) c2 (CHead e2 (Bind b)
-(lift1 (match (blt (trans hds0 i) d) with [true \Rightarrow (PCons h (minus d
-(S (trans hds0 i))) (ptrans hds0 i)) | false \Rightarrow (ptrans hds0 i)])
-v)))))))))))) with [(drop1_nil c) \Rightarrow (\lambda (H2: (eq PList PNil
-(PCons h d hds0))).(\lambda (H3: (eq C c c2)).(\lambda (H4: (eq C c
-c1)).((let H5 \def (eq_ind PList PNil (\lambda (e: PList).(match e in PList
-return (\lambda (_: PList).Prop) with [PNil \Rightarrow True | (PCons _ _ _)
-\Rightarrow False])) I (PCons h d hds0) H2) in (False_ind ((eq C c c2) \to
-((eq C c c1) \to (ex2 C (\lambda (e2: C).(drop1 (match (blt (trans hds0 i) d)
-with [true \Rightarrow (PCons h (minus d (S (trans hds0 i))) (ptrans hds0 i))
-| false \Rightarrow (ptrans hds0 i)]) e2 e1)) (\lambda (e2: C).(getl (match
-(blt (trans hds0 i) d) with [true \Rightarrow (trans hds0 i) | false
-\Rightarrow (plus (trans hds0 i) h)]) c2 (CHead e2 (Bind b) (lift1 (match
-(blt (trans hds0 i) d) with [true \Rightarrow (PCons h (minus d (S (trans
-hds0 i))) (ptrans hds0 i)) | false \Rightarrow (ptrans hds0 i)]) v)))))))
-H5)) H3 H4)))) | (drop1_cons c0 c3 h0 d0 H2 c4 hds1 H3) \Rightarrow (\lambda
-(H4: (eq PList (PCons h0 d0 hds1) (PCons h d hds0))).(\lambda (H5: (eq C c0
-c2)).(\lambda (H6: (eq C c4 c1)).((let H7 \def (f_equal PList PList (\lambda
-(e: PList).(match e in PList return (\lambda (_: PList).PList) with [PNil
-\Rightarrow hds1 | (PCons _ _ p) \Rightarrow p])) (PCons h0 d0 hds1) (PCons h
-d hds0) H4) in ((let H8 \def (f_equal PList nat (\lambda (e: PList).(match e
-in PList return (\lambda (_: PList).nat) with [PNil \Rightarrow d0 | (PCons _
-n _) \Rightarrow n])) (PCons h0 d0 hds1) (PCons h d hds0) H4) in ((let H9
-\def (f_equal PList nat (\lambda (e: PList).(match e in PList return (\lambda
-(_: PList).nat) with [PNil \Rightarrow h0 | (PCons n _ _) \Rightarrow n]))
-(PCons h0 d0 hds1) (PCons h d hds0) H4) in (eq_ind nat h (\lambda (n:
-nat).((eq nat d0 d) \to ((eq PList hds1 hds0) \to ((eq C c0 c2) \to ((eq C c4
-c1) \to ((drop n d0 c0 c3) \to ((drop1 hds1 c3 c4) \to (ex2 C (\lambda (e2:
-C).(drop1 (match (blt (trans hds0 i) d) with [true \Rightarrow (PCons h
-(minus d (S (trans hds0 i))) (ptrans hds0 i)) | false \Rightarrow (ptrans
-hds0 i)]) e2 e1)) (\lambda (e2: C).(getl (match (blt (trans hds0 i) d) with
-[true \Rightarrow (trans hds0 i) | false \Rightarrow (plus (trans hds0 i)
-h)]) c2 (CHead e2 (Bind b) (lift1 (match (blt (trans hds0 i) d) with [true
-\Rightarrow (PCons h (minus d (S (trans hds0 i))) (ptrans hds0 i)) | false
-\Rightarrow (ptrans hds0 i)]) v)))))))))))) (\lambda (H10: (eq nat d0
-d)).(eq_ind nat d (\lambda (n: nat).((eq PList hds1 hds0) \to ((eq C c0 c2)
-\to ((eq C c4 c1) \to ((drop h n c0 c3) \to ((drop1 hds1 c3 c4) \to (ex2 C
-(\lambda (e2: C).(drop1 (match (blt (trans hds0 i) d) with [true \Rightarrow
-(PCons h (minus d (S (trans hds0 i))) (ptrans hds0 i)) | false \Rightarrow
-(ptrans hds0 i)]) e2 e1)) (\lambda (e2: C).(getl (match (blt (trans hds0 i)
-d) with [true \Rightarrow (trans hds0 i) | false \Rightarrow (plus (trans
-hds0 i) h)]) c2 (CHead e2 (Bind b) (lift1 (match (blt (trans hds0 i) d) with
-[true \Rightarrow (PCons h (minus d (S (trans hds0 i))) (ptrans hds0 i)) |
-false \Rightarrow (ptrans hds0 i)]) v))))))))))) (\lambda (H11: (eq PList
-hds1 hds0)).(eq_ind PList hds0 (\lambda (p: PList).((eq C c0 c2) \to ((eq C
-c4 c1) \to ((drop h d c0 c3) \to ((drop1 p c3 c4) \to (ex2 C (\lambda (e2:
-C).(drop1 (match (blt (trans hds0 i) d) with [true \Rightarrow (PCons h
-(minus d (S (trans hds0 i))) (ptrans hds0 i)) | false \Rightarrow (ptrans
-hds0 i)]) e2 e1)) (\lambda (e2: C).(getl (match (blt (trans hds0 i) d) with
-[true \Rightarrow (trans hds0 i) | false \Rightarrow (plus (trans hds0 i)
-h)]) c2 (CHead e2 (Bind b) (lift1 (match (blt (trans hds0 i) d) with [true
-\Rightarrow (PCons h (minus d (S (trans hds0 i))) (ptrans hds0 i)) | false
-\Rightarrow (ptrans hds0 i)]) v)))))))))) (\lambda (H12: (eq C c0
-c2)).(eq_ind C c2 (\lambda (c: C).((eq C c4 c1) \to ((drop h d c c3) \to
-((drop1 hds0 c3 c4) \to (ex2 C (\lambda (e2: C).(drop1 (match (blt (trans
-hds0 i) d) with [true \Rightarrow (PCons h (minus d (S (trans hds0 i)))
-(ptrans hds0 i)) | false \Rightarrow (ptrans hds0 i)]) e2 e1)) (\lambda (e2:
-C).(getl (match (blt (trans hds0 i) d) with [true \Rightarrow (trans hds0 i)
-| false \Rightarrow (plus (trans hds0 i) h)]) c2 (CHead e2 (Bind b) (lift1
-(match (blt (trans hds0 i) d) with [true \Rightarrow (PCons h (minus d (S
-(trans hds0 i))) (ptrans hds0 i)) | false \Rightarrow (ptrans hds0 i)])
-v))))))))) (\lambda (H13: (eq C c4 c1)).(eq_ind C c1 (\lambda (c: C).((drop h
-d c2 c3) \to ((drop1 hds0 c3 c) \to (ex2 C (\lambda (e2: C).(drop1 (match