proposition: Lemma dsube_le0 x y : (x \is a fin_num) || (y \is a fin_num) -> (y - x <= 0) = (y <= x).
proof: Proof. by move=> /orP[?|?]; [rewrite dsuber_le0|rewrite dsubre_le0]. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra) signed