proposition: Lemma ger_nMr x y : y < 0 -> (y * x <= y) = (1 <= x).
proof: Proof. by move=> hy; rewrite -{2}[y]mulr1 ler_nM2l. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)