proposition: Lemma cnv2I (F: graph2): F°° ≃2 F.
proof: Proof. by case F. Qed.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom mgraph ptt)