proposition: Lemma reachable_through_set_app_right: forall g S1 S2 x, reachable_through_set g S2 x -> reachable_through_set g (S1 ++ S2) x.
proof: Proof. intros. rewrite <- reachable_through_set_app; tauto. 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