proposition: Lemma pfoot_last: forall (g: Gph) p n s, pfoot g (s, p +:: n) = dst g n.
proof: Proof. intros. induction p. 1: simpl; auto. rewrite <- app_comm_cons. simpl in *. destruct (p +:: n) eqn:? . + destruct p; inversion Heql. + 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