(****************)
simple induction v. unfold strip in |- *. simpl in |- *. trivial with arith.
simple induction i; simple induction j. rewrite trunc_O. rewrite strip_O. auto with arith.
intros. rewrite strip_O. rewrite strip_O. auto with arith.
rewrite trunc_O. elim plus_n_O. rewrite strip_trunc_i. trivial with arith.
intros.
rewrite strip_cons_S. replace (S n + S n0) with (S (n + S n0)).
simpl in |- *. rewrite strip_cons_S. apply H.
auto with arith.
Qed.
(****************************************************************)
(* lemmes sur elemlist et sublist *)

Lemma elemlist_is_sublist :
forall (v : list A) (i : nat),
elemlist v i = sublist v i 1.