proposition: Lemma sigma_algebra0 : <<s D, G >> set0.
proof: Proof. by case: smallest_sigma_algebra. 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)