proposition: Lemma oiso2_id G (isG : is_graph G) : G ⩭2 G.
proof: Proof. econstructor. exact: iso2_id. Defined.
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)