proposition: Lemma ler_pdivrMl z x y : 0 < z -> (z^-1 * y <= x) = (y <= z * x).
proof: Proof. by move=> z_gt0; rewrite mulrC ler_pdivrMr ?[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)