proposition: Lemma measurable_set1 (r : R) : measurable [set r].
proof: Proof. rewrite set1_bigcap_oc; apply: bigcap_measurable => k // _. by apply: sub_sigma_algebra; exact/is_ocitv. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum ssrint interval) mathcomp(finmap fingroup perm rat) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop) reals ereal signed topology numfun normedtype HB(structures) sequences esum measure real_interval realfun exp lebesgue_stieltjes_measure