proposition: Lemma Intersection_spec: forall A (v: A) P Q, Intersection _ P Q v <-> P v /\ Q v.
proof: Proof. intros. split; intros. + inversion H; auto. + constructor; tauto. Qed.
imports: Coq.Classes.Morphisms Coq.Classes.Equivalence Coq.Sets.Ensembles Coq.Sets.Constructive_sets CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext