proposition: Lemma merge_surjE (x: G): merge_surj (\pi x) = fv x.
proof: Proof. by rewrite quot_kernelE. Qed.
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)