proposition: Lemma mem_one_eq : forall x y, mem x (y::nil) = (x = y).
proof: Proof. Proof using. intros. extens. iff H; inverts~ H. false_invert. Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)