proposition: Lemma Iff_right: forall (A B C : CProp), (A IFF B) -> (A IFF C) -> (B IFF C).
proof: Proof. unfold Iff. intuition. Qed.
imports: Coq.Arith.Compare_dec CoRN.logic.CornBasics Coq.ZArith.ZArith Coq.setoid_ring.ZArithRing Coq.Arith.Wf_nat Coq(Lia)