proposition: Lemma min_R : forall x y , min x y = y <-> y <= x.
proof: Proof. split;intros. destruct H. apply Nat.le_min_l. apply min_r;trivial. Qed.
imports: Coq(List) JML(Stack) Coq(ListSet) Coq(Bool) Coq(ZArith) Coq(Relation_Operators) JML(ListHelpers) Coq(Classical)