proposition: Lemma indic_fubini_tonelli1 : \int[m1 \x m2]_z (f z)%:E = \int[m1]_x F x.
proof: Proof. by rewrite /f integral_indic// setIT indic_fubini_tonelli_FE. 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