fact: Definition actm (x y : A * (B * C)) : {hom x,y} -> {hom acto x, acto y} := match x, y with (xa, (xb, xc)), (ya, (yb, yc)) => fun f => pairhom (pairhom (homfst f) (homfst (homsnd f))) (homsnd (homsnd f)) end.
imports: mathcomp(all_ssreflect) mathcomp(boolp) monae_lib category HB(structures)