proposition: Lemma tailVertex_foot: forall v l e' v', tailVertex v (l +:: (e', v')) = v'.
proof: Proof. intros. revert v. induction l; simpl; auto. destruct a; auto. Qed.
imports: Coq.Classes.Morphisms Coq.micromega.Lia Coq.Logic.FunctionalExtensionality CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.lib.EnumEnsembles CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.graph_gen CertiGraph.graph.FiniteGraph