proposition: Lemma merge_union_KE (x: F+K): merge_union_K (\pi x) = \pi (sum_left k x).
proof: Proof. by rewrite /=quot_union_KE quot_sameE. Qed.
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)