proposition: Lemma lte_dsuber_addr x y z : y \is a fin_num -> (x < y - z) = (x + z < y).
proof: Proof. by move=> ?; rewrite !dual_addeE lteNl lteNr lte_subel_addr ?fin_numN. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra) signed