proposition: Lemma le0_fin_numE x : x <= 0 -> (x \is a fin_num) = (-oo < x).
proof: Proof. by move: x => [x| |]//=; rewrite lee_fin => x0; rewrite ltNyr. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra) signed