fact: Definition mark (root : V) (g1 : Graph) (g2 : Graph) : Prop := let PV := reachable_by g1 root (unmarked g1) in (predicate_partialgraph g1 (Complement _ PV)) ~=~ (predicate_partialgraph g2 (Complement _ PV)) /\ (forall n, marked g2 n <-> (marked g1 n \/ PV n)).
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