proposition: Lemma reachable_edge: forall (g : Gph) x y z, reachable g x y -> edge g y z -> reachable g x z.
proof: Proof. intros. eapply reachable_by_edge; eauto. 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