Theorem on the minorant. The denumerability of Maharam's problem

It is proved that on a normed denumerably complete Boolean algebra each continuous exterior measure majorizes at least one measure. With the aid of this result and of the Kelley numbers, Maharam's well-known problem on the seminormability and normability of Boolean algebras is transformed to a problem on the additive minorants of semimeasures continuous from one side on denumerable algebras.