proposition: Lemma integralEindic (D : set T) (mD : measurable D) (f : T -> \bar R) : \int[mu]_(x in D) f x = \int[mu]_(x in D) (f x * (\1_D x)%:E).
proof: Proof. by rewrite -integral_setI_indic// setIid. 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