proposition: Lemma ler_pdivlMl z x y : 0 < z -> (x <= z^-1 * y) = (z * x <= y).
proof: Proof. by move=> z_gt0; rewrite mulrC ler_pdivlMr ?[z * _]mulrC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)