(******************)
simple induction v. auto with arith.
simple induction i. auto with arith.
intros. simpl in |- *. rewrite strip_cons_S. apply H.
Qed. Hint Resolve strip_trunc_i.

Lemma strip_trunc :
forall (v : list A) (i j : nat),
strip (trunc v i) j = trunc (strip v j) (i - j).