proposition: Lemma mem_remove : forall a x l, mem x l -> x <> a -> mem x (remove a l).
proof: Proof. Proof using. intros. rewrite* mem_remove_eq. Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)