proposition: Lemma mulq_subdefE x y : mulq_subdef x y = (x.1 * y.1, x.2 * y.2).
proof: Proof. by case: x y => [x1 [[|[|x2]]|x2]] [y1 [[|[|y2]]|y2]]/=; rewrite ?Monoid.simpm. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg countalg div ssrnum) mathcomp(ssrint prime archimedean)