New posts in descriptive-set-theory

Bijection between closed uncountable subset of $\Bbb R$ and $\Bbb R$.

A Borel set whose projection onto the first coordinate is not a Borel set

Does a continuous and 1-1 function map Borel sets to Borel sets?

Borel hierarchy doesn't "collapse" before $\omega_1$

What are some good intuitions for understanding Souslin's operation $\mathcal{A}$?

Universally measurable sets of $\mathbb{R}^2$

Finitely Additive not Countably Additive on $\Bbb N$

What's the difference between rationals and irrationals - topologically?

Countable compact spaces as ordinals

Correspondences between Borel algebras and topological spaces

Examples of uncountable sets with zero Lebesgue measure

Where do Cantor sets naturally occur?

Constructing a subset not in $\mathcal{B}(\mathbb{R})$ explicitly

Is there a $\sigma$-algebra on $\mathbb{R}$ strictly between the Borel and Lebesgue algebras?

Why do we study Polish spaces?

Generic Elements of a Set.

Polish Spaces and the Hilbert Cube

Continuous functions are differentiable on a measurable set?

What is the cardinality of the set of all topologies on $\mathbb{R}$?

How to construct a Bernstein set and what are their applications?