proposition: Lemma mark_marked: forall (g1: Graph) root (g2: Graph), mark root g1 g2 -> forall n, marked g1 n -> marked g2 n.
proof: Proof. intros. destruct H as [_ ?]. rewrite H. auto. 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