proposition: Lemma eqvG_pack (G H : pre_graph) (isG : is_graph G) (isH : is_graph H) : G ≡G H -> pack G ≃2 pack H.
proof: Proof. move/eqvG_iso2 => h. apply: iso2_comp _ (iso2_comp (@oiso2_iso _ _ h) _); apply: pack_irrelevance. Qed.
imports: Coq(Relation_Definitions Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom mgraph mgraph2) GraphTheory(rewriting open_confluence finmap_plus)