proposition: Lemma triple_mark_aux1': forall g PV1 root marked', marked' = Union _ (marked g) (eq root) -> Same_set (Union V PV1 marked') (Union V (Union _ PV1 (eq root)) marked').
proof: Proof. intros. subst. rewrite Same_set_spec; intro v. rewrite !Union_spec. tauto. Qed.
imports: Coq.Logic.ProofIrrelevance Coq.Classes.Morphisms VST.msl.Coqlib2 CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.lib.Relation_ext CertiGraph.lib.relation_list CertiGraph.lib.EnumEnsembles CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.reachable_computable CertiGraph.graph.reachable_ind CertiGraph.graph.graph_gen CertiGraph.graph.subgraph2 CertiGraph.graph.dual_graph