proposition: Lemma lee_subel_addr x y z : z \is a fin_num -> (x - y <= z) = (x <= z + y).
proof: Proof. move: x y z => [x| |] [y| |] [z| |] _ //=; rewrite ?leey ?leNye //. by rewrite !lee_fin lerBlDr. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra) signed