proposition: Lemma ble_1: forall N1 N2, ble N1 N2 = true -> le N1 N2.
proof: Proof. unfold ble, le, In; intros. destruct (isempty N1) eqn:E. elim (isempty_1 _ _ E H0). apply andb_prop in H. destruct H as [B1 B2]. apply Zinf.ble_1 in B1. apply Zinf.ble_1 in B2. intuition. Qed.
imports: Coq(ZArith Psatz Bool String List FMaps) Coq(FunctionalExtensionality) CDF(Sequences IMP)