proposition: Lemma measurable_sfun_inP {d} {aT : measurableType d} {rT : realType} (f : {mfun aT >-> rT}) D (y : rT) : measurable D -> measurable (D `&` f @^-1` [set y]).
proof: Proof. by move=> Dm; apply: measurableI. 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