proposition: Lemma gamma_left_reachable_included: forall (g: Graph) x d l r, vvalid g x -> vgamma g x = (d, l, r) -> Included (reachable g l) (reachable g x).
proof: Proof. intros. intro y; intros. apply edge_reachable_by with l; auto. split; auto. split. + apply reachable_head_valid in H1; auto. + rewrite (gamma_step _ _ _ _ _ H H0). auto. Qed.
imports: CertiGraph.lib.Ensembles_ext Coq.Lists.List VST.msl.seplog VST.msl.log_normalize CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.msl_ext.log_normalize CertiGraph.msl_ext.iter_sepcon CertiGraph.msl_ext.seplog CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.reachable_computable CertiGraph.graph.reachable_ind CertiGraph.graph.subgraph2 CertiGraph.graph.graph_gen CertiGraph.graph.BinGraph CertiGraph.graph.MathGraph CertiGraph.graph.FiniteGraph CertiGraph.msl_application.Graph Coq.Logic.Classical