proposition: Lemma ltr_pM2r x : 0 < x -> {mono *%R^~ x : x y / x < y}.
proof: Proof. by move=> x_gt0; apply: leW_mono (ler_pM2r _). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)