proposition: Lemma aux18: Same_set (Union _ PV3 (eq root)) (Union _ (Union _ PV1 (eq root)) PV0).
proof: Proof. intros. rewrite aux01. rewrite Same_set_spec; intro v. rewrite !Union_spec; tauto. Qed.
imports: CertiGraph.lib.Coqlib CertiGraph.lib.Ensembles_ext CertiGraph.lib.EquivDec_ext CertiGraph.lib.relation_list CertiGraph.lib.Morphisms_ext CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.graph_gen CertiGraph.graph.graph_relation CertiGraph.graph.subgraph2 CertiGraph.graph.graph_morphism