proposition: Lemma ler_wnM2l x : x <= 0 -> {homo *%R x : y z /~ y <= z}.
proof: Proof. by move=> x_le0 y z leyz; rewrite -![x * _]mulrNN ler_wpM2l ?lterNE. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)