proposition: Lemma sfun_subring_closed : subring_closed (@sfun d aT rT).
proof: Proof. by split=> [|f g|f g]; rewrite ?inE/= ?rpred1//; move=> /andP[/= mf ff] /andP[/= mg fg]; rewrite !(rpredB, rpredM). Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum ssrint interval finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) signed reals ereal topology normedtype sequences real_interval esum measure lebesgue_measure numfun