proposition: Lemma sub_sigma_algebra2 M : M `<=` G -> <<s D, M >> `<=` <<s D, G >>.
proof: Proof. exact: sub_smallest2r. 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)