proposition: Lemma neg_pure_from_vertices_at: forall (g: Graph) (P Q: V -> Prop), (forall (x: V) (gx: GV), Q x -> @derives _ SGP_ND (vertex_at x gx) FF) -> vertices_at P g |-- !! (Disjoint _ P Q).
proof: Proof. intros. unfold vertices_at. apply neg_pure_from_pred_sepcon. intros. unfold graph_vcell. apply H; auto. Qed.
imports: Coq.Logic.Classical VST.msl.seplog VST.msl.log_normalize VST.msl.ramification_lemmas CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.lib.EnumEnsembles CertiGraph.lib.List_ext CertiGraph.lib.Relation_ext CertiGraph.lib.Equivalence_ext CertiGraph.lib.Morphisms_ext CertiGraph.msl_ext.log_normalize CertiGraph.msl_ext.iter_sepcon CertiGraph.msl_ext.ramification_lemmas CertiGraph.msl_ext.abs_addr CertiGraph.msl_ext.seplog CertiGraph.graph.graph_model CertiGraph.graph.graph_gen CertiGraph.graph.path_lemmas CertiGraph.graph.reachable_computable CertiGraph.graph.reachable_ind CertiGraph.graph.subgraph2 CertiGraph.graph.dag CertiGraph.graph.FiniteGraph