proposition: Lemma edgeless_GG_evalid: forall e, ~ evalid edgeless_GG e.
proof: Proof. intros. unfold edgeless_GG; simpl. auto. Qed.
imports: VST.floyd.proofauto CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.graph_gen CertiGraph.graph.FiniteGraph CertiGraph.graph.undirected_graph