proposition: Lemma merge2_same' (F : graph2) (h k: equiv_rel F): (h =2 k) -> merge2 F h ≃2 merge2 F k.
proof: Proof. intro. by apply merge2_same. Qed.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom mgraph ptt)