proposition: Lemma dle0_muleDr x y z : y <= 0 -> z <= 0 -> x * (y + z) = x * y + x * z.
proof: Proof. by move=> *; rewrite !dual_addeE muleN ge0_muleDr ?oppe_ge0 ?muleN. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra) signed