proposition: Lemma integral_mkcondr D P f : \int[mu]_(x in D `&` P) f x = \int[mu]_(x in D) (f \_ P) x.
proof: Proof. by rewrite integral_mkcond [RHS]integral_mkcond patch_setI. 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