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We investigate game-theoretic variants of cardinal invariants of the continuum. The invariants we treat are the splitting number $\mathfrak{s}$, the reaping number $\mathfrak{r}$, the bounding number $\mathfrak{b}$, the dominating number $\mathfrak{d}$, and the additivity number of the null ideal $\operatorname{add}(\mathsf{null})$. By using games on splitting families, we find a new cardinal invariant that differs from previously studied cardinal invariants. We also consider games, called tallness games, defined according to ideals on $\omega$ and characterize that each of Player I and Player II has a winning strategy., Comment: 27 pages

We introduce new cardinal invariants of a poset, called the comparability number and the incomparability number. We determine their value for well-known posets, such as $\omega^\omega$, $\mathcal{P}(\omega)/\mathrm{fin}$, the Turing degrees $\mathcal{D}$, the quotient algebra $\mathsf{Borel}(2^\omega)/\mathsf{null}$, the ideals $\mathsf{meager}$ and $\mathsf{null}$. Moreover, we consider these invariants for the Rudin-Keisler ordering of the nonprincipal ultrafilters on $\omega$. We also consider these invariants for ideals on $\omega$ and on $\omega_1$., Comment: 14 pages

Goldstern showed in his 1993 paper that the union of a real-parametrized, increasing family of Lebesgue measure zero sets has also Lebesgue measure zero provided that the sets are uniformly $\boldsymbol{\Sigma}^1_1$. Our aim is to study to what extent we can drop the $\boldsymbol{\Sigma}^1_1$ assumption. We show that $\mathsf{CH}$ implies the negation of Goldstern's principle for the pointclass of all subsets. Moreover we show that Goldstern's principle for the pointclass of all subsets is consistent with $\mathsf{ZFC}$. Also we prove that Goldstern's principle for the pointclass of all subsets holds both under $\mathsf{ZF} + \mathsf{AD}$ and in Solovay models.

We consider cardinal invariants determined from Hausdorff measures. We separate many cardinal invariants of Hausdorff measure $0$ ideals using two models that separate many cardinal invariants of Yorioka ideals at once from earlier work. Also we show the uniformity numbers of $s$-dimensional Hausdorff measure $0$ ideals for $0 < s < 1$ and that of Lebesgue null ideal can be separated using the Mathias forcing.