proposition: Lemma aux20: Same_set (Union _ PE3 PE3_root) (Union _ (Union _ PE3 PE1_root) (eq e0)).
proof: Proof. intros. rewrite aux03. rewrite Same_set_spec; intro e. 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