proposition: Lemma epath_to_vpath_phead: forall g p l a, valid_path g p -> epath_to_vpath g p = a :: l -> phead p = a.
proof: Proof. intros. destruct p. simpl. destruct l0; simpl in *. inversion H0; auto. destruct H. subst v. destruct l0; inversion H0; 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