Let $\omega$ be a [nonprincipal ultrafilter][1] on $\mathbb N$. A standard construction gives an $\omega$-limit, say $x_\omega$, for any bounded sequence $(x_n)$ of real numbers. Namely, there is unique real value $x_\omega$ such that $$\{\,n\in\mathbb N\mid |x_\omega-x_n|<\varepsilon\,\}\in \omega$$ for any $\varepsilon>0$. Clearly $x_\omega$ is a partial limit of $x_n$ [i.e., $x_\omega$ is a limit of a subsequence of $(x_n)$]. >**Question.** Is it always possible to choose subsequence $(x_n)$, $n\in J$ converging to $x_\omega$ and such that $J\in\omega$? [1]: http://en.wikipedia.org/wiki/Ultrafilter