(* This file is copied from RamifyCoq project. *)
Require Coq.Setoids.Setoid.
Require Export Coq.Classes.Equivalence.
Require Export Coq.Sets.Ensembles.
intros.
split; intros [].
Qed.
Arguments Included {U} B C.
Arguments Same_set {U} B C.

Lemma Same_set_sym: forall A (S1 S2 : Ensemble A), Same_set S1 S2 -> Same_set S2 S1. Proof. intros; destruct H; split; auto. Qed.