Masterclass on Groups, boundary actions and group C*-algebras

The University of Copenhagen

13-17 April 2015


The purpose of this PhD Master class is to present the recent developments and applications of the theory of Poisson-Furstenberg boundaries of a group, both from the probabilistic approach, and from the new operator algebraic perspective.

Click HERE to download the group photo. See more photos.


The main lecture series will be delivered by:

There is also a special Harald Bohr Lecture by Efim Zelmanov on Tuesday, April 14, at 15:15.

Titles and abstracts:

  • Emmanuel Breuillard: Random Walks and Spectral Gaps.
  • Vadim Kaimanovich: Boundary of groups: geometry, probability and analysis.
  • Matthew Kennedy: Boundaries, injectivity and C*-simplicity for discrete groups.
  • Robin Tucker-Drob: Group invariant means and inner amenability.

Click HERE for abstracs.

Notes for the lectures:

Notes taken by Hiroshi Ando:


The program can be found HERE.


The lectures will be held at the Department of Mathematical Sciences at the University of Copenhagen, and the event is hosted by the Centre for Symmetry and Deformation.

You can find information for short term visitors including directions to the mathematics department HERE. And HERE you can find a map with the HCØ building and the math department.


We recommend Hotel de 9 Små Hjem, which is pleasant and inexpensive and offers room with a kitchen. Other inexpensive alternatives are CabInn that has several locations in Copenhagen: the Hotel City (close to Tivoli), Hotel Scandivania (Frederiksberg, close to the lakes), and Hotel Express (Frederiksberg) are the most convenient locations; the latter two are 2.5-3 km from the math department.

Somewhat more expensive - and still recommended - options are Hotel Nora and Ibsen's Hotel. Invited speakers need not reserve hotel rooms (this will be taken care of by the organizers). 


Participants can apply for support to partly cover their living costs while attending the masterclass. The support will be DKK 500 per day, and it will primarily be given to participating PhD students and postdocs.

Deadline for applying for support is March 13, 2015. (Has expired)


Please register for the Masterclass by filling in this registration form.  Registration is free.

Deadline for registration is March 27, 2015. (Has expired)


List of participants can be found HERE.

Organizers: Magdalena Musat, Mikael Rørdam,