Circular orders, ultra-homogeneity and topological groups

יום ב', 15/01/2018 - 13:00
A circular order on a set is, intuitively speaking, a linear order which has been bent into a ``circle". 
In the first part we give necessary background, examples and motivation. 
In the second part we present some applications (joint results with E. Glasner) 
in symbolic dynamical systems and topological groups. 
We study ultra-homogeneous actions on circularly ordered sets and prove a  "circular" analog of 
V. Pestov's well known result about ultra-homogeneous actions on linearly ordered sets.