proposition: Lemma add_neq_mapsto_iff : forall m x y e e', x <> y -> (MapsTo y e' (add x e m) <-> MapsTo y e' m).
proof: Proof. split; [apply add_3|apply add_2]; auto. Qed.
imports: SetoidList Bool OrderedType OrdersLists RelationPairs Orders RelationClasses