proposition: Lemma union_merge_rEr (x: G): union_merge_r (@unr _ _ _ (merge_seq G l) (\pi x)) = \pi (unr x).
proof: Proof. rewrite /=. rewrite (union_merge_lEl F _ x). rewrite (merge_isoE (union_C G F) _ (unl x)). by rewrite merge_sameE. Qed.
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)