proposition: Lemma preimage_class_measurable_fun d (aT : pointedType) (rT : measurableType d) (D : set aT) (f : aT -> rT) : measurable_fun (D : set (salgebraType (preimage_class D f measurable))) f.
proof: Proof. by move=> mD A mA; apply: sub_sigma_algebra; exists A. Qed.
imports: mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) reals ereal signed topology normedtype sequences esum numfun HB(structures)