proposition: Lemma lef_pV2 : {in pos &, {mono (@GRing.inv F) : x y /~ x <= y}}.
proof: Proof. by move=> x y hx hy /=; rewrite ler_pV2 ?inE ?unitf_gt0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)