proposition: Lemma ltr_pdivrMr z x y : 0 < z -> (y / z < x) = (y < x * z).
proof: Proof. by move=> z_gt0; rewrite -(@ltr_pM2r _ z) ?mulfVK ?gt_eqF. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)