proposition: Lemma lte_dadd2lE x a b : x \is a fin_num -> (x + a < x + b) = (a < b).
proof: Proof. by move=> ?; rewrite !dual_addeE lteN2 lteD2lE ?fin_numN// lteN2. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra) signed