Assume that is an ideal on , and is a divergent series in a Banach space . We study the Baire category, and the measure of the set $A():=\left{t \in {0,1}^{} \colon \sum_n t(n)x_n \right}$. In the category case, we assume that has the Baire property and $\sum_n x_nA()$ is meager. We also study the smallness of in the measure case when the Haar probability measure on is considered. If is analytic or coanalytic, and is -divergent, then which extends the theorem of Dindo\v{s}, \v{S}al'at and Toma. Generalizing one of their examples, we show that, for every ideal on , with the property of long intervals, there is a divergent series of reals such that and .

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