Devrim Pekmezci : Ellis Group Conjecture

Posted by Ryan Carpenter , part of the Louise Hay Logic Seminar.

At

Oct. 29, 2025, 4 p.m.

In

427 SEO

Abstract

Newelski introduced tools from topological dynamics into model theory to generalize the notion of a generic type from stable group theory to arbitrary first-order theories. He adapted Ellis’s theory to the definable setting and introduced what is now known as the Ellis Group Conjecture, which relates the Ellis group of the space of types concentrating on a definable group G, viewed as a G-flow, to the maximal compact quotient of G, a model-theoretic invariant, under suitable tameness assumptions. The conjecture has been established for definably amenable groups in NIP theories by Chernikov and Simon. In this talk, we will outline the conjecture’s motivation, introduce the key concepts surrounding it, and discuss possible directions for further research.