proposition: Lemma vgamma_not_dst: forall (g: UFGraph) x r pa, vgamma g x = (r, pa) -> pa <> x -> dst g (out_edge x) = pa.
proof: Proof. intros. unfold vgamma in H. destruct (projT2 isNullDec (dst g (out_edge x))); inversion H; [exfalso |]; auto. Qed.
imports: Coq.Sets.Ensembles Coq.Lists.List CertiGraph.lib.EquivDec_ext CertiGraph.lib.Coqlib CertiGraph.lib.Ensembles_ext CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.reachable_computable CertiGraph.graph.graph_gen CertiGraph.graph.FiniteGraph CertiGraph.graph.MathGraph CertiGraph.graph.LstGraph CertiGraph.graph.UnionFind