New posts in Descriptive Set Theory

Question about additive subgroups of the real line and the density topology

Set of perfect subsets of a Borel set

On the absoluteness of higher Borel sets?

How (non-)computable is set theory?

The "strong" measure number

Given a sequence of reals, we can find a dense sequence avoiding it, but can we find one continuously?

measurable linear functionals are also continuous on separable Banach spaces?

What is the descriptive complexity of a set added by Cohen forcing?

How to show that something is not completely metrizable

Is there a Borel subset of $ \mathbb{R}^{2} $, with finite vertical cross-sections, whose projection onto the first component is non-Borel?