proposition: Lemma good_path_tail: forall (g: Gph) P p, good_path g P p -> good_path g P (ptail g p).
proof: Proof. intros. destruct H. split; [apply valid_path_tail | apply path_prop_tail]; 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