# Dana Bartošová: Ellis problem for automorphism groups

The seminar meets on Wednesday January 10th at 11:00 in the Institute of
Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program: Dana Bartošová — Ellis problem for automorphism groups

Abstract: It is an old problem of Ellis to determine whether two
prominent dynamical system of a given topological group are isomorphic.
For discrete groups, only the integers are known to be a counterexample
by a complex result of Glasner and Weiss. Trivially, groups acting with
a fixed point under any action are counterexamples. We extend the class
of counterexamples to a few automorphism groups and we will have a
closer look at the full permutation group, $S_{\infty}$. This leads us
to questions about the existence of certain ultrafilters on natural
numbers. This is a joint work with Andy Zucker.