fact: Definition h_union_merge_l: bij (merge_seq F l ⊎ G)%G (merge_seq (F ⊎ G) (map_pairs unl l)).
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)