# Rigidity 2009 in Bonn

## Seminars 28.9. – 2.10.

In Talk announcement on September 29, 2009 at 10:12

Tuesday, 3 pm: Rigidity and algebraic K-theory (concerning the Borel conjecture), Wolfgang Steimle

## Let’s talk about your problems!

In Talk announcement on September 24, 2009 at 13:42

Wednesday 30 Sept, 10:00 AM: Presentation and discussion of open problems related to rigidity.

Everybody is invited!

## Seminars 21.-25.9.

In Talk announcement on September 16, 2009 at 10:09

Tuesday 9 am: A Counterexample to Atiyah´s Conjecture I (after Tim Austin), Thomas Schick

Tuesday 3 pm: Borel reducibility, Asger Törnquist

Wednesday 9 am: A Counterexample to Atiyah´s Conjecture II (after Tim Austin), Thomas Schick

Wednesday 3 pm: Cohomology of Lie groups, Tobias Hartnick

Thursday 9 am: Simplicial Volume, Clara Löh

Thursday 3 pm: What is coarse differentiation?, Irene Peng

Friday 9 am: Quantum groups for beginners, David Kyed

## LaTeX in this blog!

In Uncategorized on September 14, 2009 at 15:10

We can use some amount of $\LaTeX$ in this blog. Just put any math command between $signs, with the word “latex” (followed by a space) right after the first$.

Thus, for instance, if I write this:

$latex \sum_{n=1}^\infty \frac1{n^2} = \frac{\pi^2}6$,

you will see that:

$\sum_{n=1}^\infty \frac1{n^2} = \frac{\pi^2}6$.

Of course, only basic commands will work. Enjoy!

Nicolas

## Seminars 14-18.9

In Talk announcement on September 11, 2009 at 16:03

Wed 3pm: Hjorth, Descriptive set theory and equivalence relations.
Abstract: A very general and introductory talk about descriptive set
theory and the parts of the field which connect with countable
equivalence relations.

Thu 9am: Przytycki, Introduction to complexes of groups,.

## Seminar talks (Archiv)

In Talk announcement on September 9, 2009 at 15:08

Just to keep the list of seminar talks up to date and not to lose the information which talks have already be given, I suggest to list past talks in this post. Also, one might use this post to add background material or references to the old talks.

The following talks have already be given:

• Caprace, Kac-Moody groups
• Fabig, Assembly maps
• Weinberger, Topological Rigidity
• Sauer, Measure equivalence
• Chatterjee, Algebraic Groups
• Ruping, CAT(0) properties of diagram groups
• Epstein, Orbit equivalence
• Hjorth, Descriptive Set Theory
• Przytycki, Complexes of groups
• Schick, A Counterexample to Atiyah´s Conjecture (after Tim Austin)
• Törnquist, Borel reducibility
• Hartnick, Cohomologies of Lie groups
• Löh, Simplicial Volume
• Peng, Coarse Differentiation
• Kyed, Quantum Groups

## Seminars

In Talk announcement on September 9, 2009 at 13:12

Wed 2pm: Weinberger, Topological Rigidity

Thu 9am: Sauer, Measure Equivalence

Thu 2pm: Chatterjee, Algebraic Groups

Fri 9am: Ruping, CAT(0) properties of diagram groups

## Welcome!

In Uncategorized on September 4, 2009 at 21:56

Welcome to the Rigidity blog! This is the place to announce talks, request talks, ask questions, or just comment away.

This site is destined to remain completely informal. Even if you plan to explain your latest idea — or doubt — to just one colleague, please consider announcing it here: a few more guests might just show up.