TheR-Borel structure on a Choquet simplex

A Dichotomy for the Mackey Borel Structure

We prove that the equivalence of pure states of a separable C*-algebra is either smooth or it continuously reduces [0, 1]N/l2 and it therefore cannot be classified by countable structures. The latter was independently proved by Kerr–Li–Pichot by using different methods. We also give some remarks on a 1967 problem of Dixmier. If E and F are Borel equivalence relations on Polish spaces X and Y , ...

Borel and Hausdorff Hierarchies in Topological Spaces of Choquet Games and Their Effectivization

What parts of classical descriptive set theory done in Polish spaces still hold for more general topological spaces, possibly T0 or T1, but not T2 (i.e. not Hausdorff)? This question has been addressed by Victor Selivanov in a series of papers centered on algebraic domains. And recently it has been considered by Matthew de Brecht for quasi-Polish spaces, a framework that contains both countably...

A Course on Borel Sets

The semantic structure of quasi-Borel spaces

Quasi-Borel spaces are a new mathematical structure that supports higher-order probability theory, first-order iteration, and modular semantic validation of Bayesian inference algorithms with continuous distributions. Like a measurable space, a quasi-Borel space is a set with extra structure suitable for defining probability and measure distributions. But unlikemeasurable spaces, quasi-Borel sp...

Variations on a Theme of Borel