proposition: Lemma merge2_same (F : graph) (h k: equiv_rel F) (i i' o o': F): (h =2 k) -> h i i' -> h o o' -> merge2 (point F i o) h ≃2 merge2 (point F i' o') k.
proof: Proof. apply merge_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)