During the academic year 2017-2018, Romain Tessera and I are organizing the weekly seminar Groups, Actions and von Neumann algebras at the Université Paris-Sud, Orsay.

The seminar features both research and introductory talks on topics including geometric and measured group theory, ergodic theory and von Neumann algebras.

#### Next Meetings

##### Monday February 19

Stefan Witzel (Bielefeld University)

*Simple groups separated by finiteness properties*

##### Monday March 19

Piotr Nowak (Polish Academy of Sciences)

*Aut(F_5) has property (T)*

##### Monday March 26

Federico Vigolo (University of Oxford)

*Warped systems of actions on metric spaces*

##### Monday April 9

Johannes Cuno (Ecole Normale Supérieure)

*Random walks on Baumslag-Solitar groups*

#### Previous Meetings

##### Monday September 25

Narutaka Ozawa (RIMS Kyoto University)

*Finite-dimensional representations constructed from random walks*

##### Monday October 2

Cyril Houdayer (Université Paris-Sud)

*The Kadison-Singer Problem (Part 1) *

##### Monday October 9

Cyril Houdayer (Université Paris-Sud)

*The Kadison-Singer Problem (Part 2)*

##### Monday November 6

Amine Marrakchi (Université Paris-Sud)

*The Kadison-Singer Problem (Part 3)*

##### Tuesday November 7

Jérémie Brieussel (Université de Montpellier)

*Shalom’s property H _{FD} and Z-extensions of locally finite groups*

##### Monday November 27

Romain Tessera (CNRS & Université Paris-Sud)

*The Kadison-Singer Problem (Part 4)*

##### Monday February 5

Yves de Cornulier (CNRS & Université Lyon 1)

*Near actions*

##### Monday February 12

Isaac Goldbring (University of California at Irvine)

*Embedding problems, games, and square roots*