Będlewo 5 May  10 May 2013
Overview
This workshop is aimed mainly at students (PhD and undergraduate) interested in geometric group theory and will take place in Będlewo (near Poznań) from the 5th until the 10th of May 2013.
The scientific programme will consist of a few lecture series and shorter talks given by the participants about their current research interests. The event will have a rather informal atmosphere, with plenty of time for discussions and interactions between the participants.
More information will appear on this page in due course.
Organizers
Marcin Kotowski, Michał Kotowski, Tomasz Prytuła, Piotr Przytycki, Paweł Zawiślak
Contact: Tomasz Prytuła
Programme
List of abstracts
Short lecture series by:

Łukasz Grabowski (University of Oxford):
L^2 invariants and decidability
I will start by introducing L^2 invariants of groups  these are invariants defined by looking at the boundary map in CWcomplexes, treated as an operator on an infinitedimensional Hilbert space. An example is the random walk operator on Z^2  we will see how this and other operators arise as boundary maps of CWcomplexes. The main part of the lecture will focus on cases where concrete calculations are possible, i.e. when we have a group which is a semidirect product, acting on a manifold. As the main application, we will see how one can study classical problems from group ring theory  in particular, the problem of the existence of zero divisors  from the perspective of decidability theory.

Piotr Przytycki (IMPAN):
Automorphisms of surfaces
In this lecture course we will give a proof of Thurston's classification of surface automorphisms. The theorem says that every surface automorphism is periodic, reducible or pseudoAnosov. We will follow the book of Casson and Bleiler, where (measured) geodesic laminations are used.

Marcin Kotowski, Michał Kotowski:
Random groups and Property (T)
In our lectures we will introduce the Gromov model of random groups, the notion of Kazhdan’s Property (T) and prove that random groups for densities d > 1/3 satisfy Kazhdan’s Property (T). Along the way we will prove the spectral criterion for property (T) and review relevant results from spectral graph theory and random graphs (random regular graphs and ErdosRenyi graphs).
In addition to the courses there will be shorter talks by the participants (the list will appear here in due course).
List of participants Sylwia Antoniuk, Adam Mickiewicz University
 Maurice Chiodo, University of Milan
 Światosław Gal, University of Wrocław
 Łukasz Garncarek, University of Wrocław
 Łukasz Grabowski, University of Oxford
 Marcin Kotowski, University of Toronto
 Michał Kotowski, University of Toronto
 Katarzyna Jankiewicz, University of Warsaw
 Michał Marcinkowski, University of Wrocław
 Tomasz Odrzygóźdź, University of Warsaw
 Damian Orlef, University of Warsaw
 Tomasz Prytuła, University of Warsaw
 Janusz Przewocki, IMPAN
 Piotr Przytycki, IMPAN
 Karol Strzałkowski, IMPAN
 Piotr Suwara, University of Warsaw
 Krzysztof Święcicki, University of Warsaw
 Robert Tang, University of Warwick/IMPAN