proposition: Lemma ble_1: forall N1 N2, ble N1 N2 = true -> le N1 N2.
proof: Proof. unfold ble, le, In; intros. destruct N1; try contradiction; destruct N2; try discriminate; auto. apply Z.eqb_eq in H. lia. Qed.
imports: Coq(ZArith Psatz Bool String List FMaps) CDF(Sequences IMP)