Masterclass on Sofic groups and applications to operator algebras

The University of Copenhagen

November 5-9, 2012


The masterclass is aimed at PhD students and postdocs. The lectures will be self contained, and no prior knowledge on Sofic groups will be assumed. There will be three lecture series as well as some more specialized talks.

Notes, references and further reading:

List of reference for David Kerr's lecture series .

Narutaka Ozawa's lecture series:

List of references for Andreas Thom's lecture series.

Gabor Elek's talks:

Nicolas Monod's talks:

Slides EK from Eberhard Kirchberg's talks.

Here is an interpretation of Banach-Tarski's paradox
 by the U. of Copenhagen students.


The lecture series will be delivered by:

In addition there will be lectures by

  • Gabor Elek, Ecole Polytechnique Federale de Lausanne.
  • Eberhard Kirchberg, Humboldt-Universität zu Berlin.
  • Nicolas Monod, Ecole Polytechnique Federale de Lausanne.


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 .Note added to the visitors guide: Bus 43 is discontinued and bus 42 does not stop at the university any more.


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. You can also check this almost up to date hotel list. Invited speakers need not reserve hotel rooms (this will be taken care of by the organizers). 


Deadline for applying for support has passed. 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. Please indicate on the registration form if you wish to be considered for this support. If you wish to be considered for support, then you must send your cv and a brief motivation for your participation in the masterclass to Uffe Haagerup (Email: 


Deadline for registration has passed.

Program and titles of lecture series:

Abstracts for the lecture series can be found HERE. The titles are:

  • David Kerr: Soficity, dynamics, and entropy.
  • Narutaka Ozawa: Connes' Embedding Problem and its equivalent.
  • Andreas Thom: Finite-dimensional approximation properties of groups and their applications.
  • Gabor Elek: Invariants and spaces of finite graph sequences and sofic approximations.
  • Eberhard Kirchberg: TBA.
  • Nicolas Monod: Simple amenable groups.
  • Nicolas Monod: Simple non-amenable groups.

The program can be found HERE.


List of participants can be found HERE.

Organizers: Magdalena Musat, Uffe Haagerup, Mikael Rørdam.