proposition: Lemma In_rev A: forall a n (v : t A n), In a (rev v) <-> In a v.
proof: Proof. intros a n v. induction v as [|b n v IH]. - now rewrite rev_nil. - now rewrite rev_cons, In_shiftin, In_cons_iff, IH. Qed.
imports: VectorDef PeanoNat Eqdep_dec