proposition: Lemma noduplicates_filter : forall P l, noduplicates l -> noduplicates (filter P l).
proof: Proof. Proof using. introv H. induction H; rew_listx. { auto. } { case_if. { constructors*. rew_listx*. } { auto. } } Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)