Masterclass: Expanders and rigidity of group actions

Department of Mathematical Sciences

The University of Copenhagen

2-6 May 2016

The purpose of this PhD Masterclass is to give an introduction to the theory of expander graphs, and present some of their recent applications to important problems in geometric (and analytic) group theory, and to operator algebras. In particular, we will address connections to rigidity properties (such as property (T) and fixed point properties) of group actions on Banach spaces. The masterclass is aimed primariy at junior researchers, such as PhD students and postdocs.



The main lecture series will be delivered by:

There is also a special Department Colloquium by Alex Lubotzky on Wednesday, May 4, at 15:15, which will be incorporated into the schedule of the Masterclass.

Titles, abstracs and program:

  • Alex Lubotzky: High dimensional expanders in pure and applied mathematics.
  • Nicolas Monod: Amenability and fixed point theorems.
  • Damian Osajda: Groups containing expanders.
  • Mikael de la Salle: Rigidity properties for group actions on Banach spaces.

Click HERE for abstracts, and HERE for the program.

Lecture notes:


The lectures will be held at the Department of Mathematical Sciences at the University of Copenhagen. The event is hosted by the Centre for Symmetry and Deformation. We also acknowledge support and funding from the Faculty of Science and from the Villum Foundation.


List of participants.

Participants 2


For questions about the meeting, please write to one of the organizers: Magdalena Musat ( or Chris Cave (

Organizers: Magdalena Musat and Chris Cave.