proposition: Lemma elabel_iso' F G (h: iso F G) e: elabel (h.e^-1 e) ≡[h.d (h.e^-1 e)] elabel e.
proof: Proof. apply (elabel_iso (iso_sym h)). Qed.
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)