proposition: Lemma aux11: Disjoint _ PE1_root (eq e0).
proof: Proof. rewrite Disjoint_spec. intros e ? ?. subst e. subst PE1_root. rewrite H_ES in H_NODUP. pose proof NoDup_app_not_in _ _ _ H_NODUP e0. simpl in H0. clear - H0 H. 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