proposition: Lemma measurable_id D : measurable_fun D id.
proof: Proof. by move=> mD A mA; apply: measurableI. 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)