proposition: Lemma split_correct : forall l n l1 l2, split l n = Some (l1, l2) -> l = l1 ++ l2.
proof: Proof. intros. change (rev' nil ++ l = l1 ++ l2). apply (split_aux_correct _ H). Qed.
imports: CoLoR(LogicUtil EqUtil RelUtil BoolUtil NatUtil) Coq(Setoid SetoidList FunInd)