Groups and Operator Algebras Seminar

Speaker: Adrian Ioana (UCSD)

Title: An exotic II_1 factor without property Gamma

Abstract: Two II_1 factors are elementarily equivalent if they admit isomorphic ultrapowers with respect to some ultrafilters on arbitrary sets. I will present a construction of a II_1 factor which does not have property Gamma and is not elementarily equivalent to a free group factor. This provides the first explicit example of two non-elementarily equivalent II_1 factors without property Gamma. Moreover, the construction also provides the first explicit example of a II_1 factor without property Gamma that is not elementarily equivalent to an ultraproduct of matrix algebras. This is joint work with Ionut Chifan and Srivatsav Kunnawalkam Elayavalli.

GOA website: https://sites.google.com/view/copenhagen-goa-seminar