proposition: Lemma reachable_through_set_reachable: forall (g: Gph) l x y, reachable_through_set g l x -> reachable g x y -> reachable_through_set g l y.
proof: Proof. intros. destruct H as [s [? ?]]; exists s; split; auto. apply reachable_trans with x; 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