proposition: Lemma vlabel_iso F G (h: iso F G) v: vlabel (h v) ≡ vlabel v.
proof: Proof. exact: vlabel_ihom. Qed.
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)