proposition: Lemma ltW x y: x < y -> x <= y.
proof: Proof. by rewrite le_eqVlt orbC => ->. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)