proposition: Lemma noduplicates_cons_eq : forall x l, noduplicates (x::l) = (~ (LibList.mem x l) /\ noduplicates l).
proof: Proof. Proof using. extens. iff M; inverts* M. Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)