Title:  Analogon of Newelski's semigroup theorem for Aut(M)-actions

Speaker：Daniel Max Hoffmann (University of Warsaw)

Time: 2024/12/11 15:00-16:00

Zoom room: 717 463 6082

Organizer: Kyle Gannon (BICMR)

Abstract：

　　This is part of my project with Kyle Gannon and Krzysztof Krupiński. We define and study a new convolution of invariant Keisler measures. To define it, we establish an analogon of Newelski's semigroup theorem, so a homeomorphism between a certain Ellis semigroup and a space of Keisler measures. Our variant of Newelski's theorem is made for Ellis semigroups related to actions of Aut(M) instead of actions of a definable group. Then we push the semigroup operation from Ellis semigroup to define a new convolution for Keisler measures and study some of its properties.