proposition: Lemma mark_markeds: forall m1 root m2, mark m1 root m2 -> ReachDecidable g root (negateP m1) -> forall n, m1 n -> m2 n.
proof: Proof. intros. destruct H as [? ?]. destruct (X n). auto. specialize (H1 n n0). tauto. Qed.
imports: Coq.Logic.ProofIrrelevance CertiGraph.lib.Ensembles_ext Coq.Lists.List Coq.Classes.Morphisms CertiGraph.lib.Coqlib CertiGraph.lib.List_ext CertiGraph.lib.EquivDec_ext VST.msl.Coqlib2 CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.reachable_computable CertiGraph.graph.reachable_ind CertiGraph.graph.graph_gen CertiGraph.graph.graph_relation CertiGraph.graph.subgraph2