proposition: Corollary open_continuous_measurable_fun (D : set R) (f : R -> R) : open D -> {in D, continuous f} -> measurable_fun D f.
proof: Proof. move=> oD; rewrite -(continuous_open_subspace f oD). by apply: subspace_continuous_measurable_fun; exact: open_measurable. 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