Effective descriptive set theory refines classical descriptive set theory by emphasising computability and algorithmic aspects in the study of definable sets and functions, particularly within Polish ...

The original version of this story appeared in Quanta Magazine. All of modern mathematics is built on the foundation of set theory, the study of how to organize abstract collections of objects. But in ...

A family $\mathscr{B}$ of Borel subsets of a space $X$ is (boundedly) Borel additive if, for some countable ordinal $\alpha$, the union of every subfamily of ...

This is a survey paper on the descriptive set theory of hereditary families of closed sets in Polish spaces. Most of the paper is devoted to ideals and σ-ideals of closed or compact sets.