proposition: Lemma Complement_Empty_set: forall A, Same_set (Complement A (Empty_set _)) (Full_set _).
proof: Proof. intros. rewrite Same_set_spec. intro a. unfold Complement, Ensembles.In. pose proof Empty_set_iff _ a. pose proof Full_set_spec _ a. tauto. Qed.
imports: Coq.Classes.Morphisms Coq.Classes.Equivalence Coq.Sets.Ensembles Coq.Sets.Constructive_sets CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext