Patrick Lutz : Borel graphable equivalence relations

Posted by Matthew Harrison-Trainor , part of the Logic Seminar.

At

Nov. 11, 2025, 3 p.m.

In

636 SEO

Abstract

In his thesis, Arant introduced and studied the notion of Borel graphability: an equivalence relation E on a Polish space X is Borel graphable if there is a Borel graph on X whose connectivity relation is equal to E. In recent work, Tyler Arant, Alexander Kechris and I have addressed the question of which equivalence relations are Borel graphable. I will discuss some of our results, including on the Borel graphability of equivalence relations generated by Polish group actions, as well as mention some open questions.