# TTT69: Sheffield

Department of Pure Mathematics, the University of Sheffield.

This was a working meeting with the usual time for participant discussion.

## Date

14 May 2009

## Speakers

### Assaf Libman (Aberdeen)

The gluing problem and Bredon cohomology

The gluing problem and Bredon cohomology

### Andras Juhasz (Cambridge)

Classifying minimal genus Seifert surfaces

Classifying minimal genus Seifert surfaces

First I will survey two different notions of equivalence for Seifert surfaces. Then I will show how sutured Floer homology helps in the classification of minimal genus Seifert surfaces under both types of equivalence.

### Michael Farber (Durham)

Topology of random manifolds

Topology of random manifolds

Betti numbers of configuration spaces of mechanical linkages (known also as polygon spaces) depend on a large number of parameters – the lengths of the bars of the linkage.

Motivated by applications in topological robotics, statistical shape theory and molecular biology, we view these lengths as random variables and study asymptotic values of the average Betti numbers as the number of links n tends to infinity. We establish a surprising fact that for a reasonably ample class of sequences of probability measures the asymptotic values of the average Betti numbers are independent of the choice of the measure.

## Further information

The meeting was partially supported by a Scheme 3 grant from the London Mathematical Society.