Large conjugacy classes and weak amalgamation

Ivanov, and later Kechris and Rosendal, characterized the existence of dense or comeager (diagonal) conjugacy classes in automorphism groups of certain classes of Fraïssé limits. I will show how these results can be extended to limits of weak Fraïssé classes, using an approach developed by Krawczyk and Kubiś. I will discuss homogenizability of weak Fraïssé classes, i.e., existence of a definable expansion to a Fraïssé class. I will also examine automorphism groups of ordered Fraïssé classes with the question in mind whether there exists a non-archimedean extremely amenable group with ample generics.

Please note that the seminar will take place in lecture hall 4420.