proposition: Lemma reachable_refl: forall (g: Gph) x, vvalid g x -> reachable g x x.
proof: Proof. intros; apply reachable_by_refl; auto. Qed.
imports: Coq.Logic.ProofIrrelevance Coq.micromega.Lia CertiGraph.lib.Coqlib CertiGraph.lib.EnumEnsembles CertiGraph.lib.List_ext CertiGraph.lib.EquivDec_ext CertiGraph.graph.graph_model Coq.Lists.List Coq.Lists.ListDec