# Model Theory Seminar

### School of Mathematics, University of Leeds

This week's seminar will be in Roger Stevens Lecture Theatre 7 and will be on Tuesday 18th March at 2pm. We will meet before the seminar at about 1.40pm in the common room for tea and coffee.

The seminar is organised by Will Anscombe.

### Spring Term 2014

Week 10, Tuesday 18th March
Cong Chen
Some combinatorial group theory

The word norm for any element of a group, given a symmetric generating set, is the length of the shortest representation of that element as a word in the generators. It may also be thought of as the graph norm on the Cayley graph. A quasimorphism from a group $G$ to a normed group (usually the Reals) is a map $f$ such that $d(f(x)f(y),f(xy))$ is absolutely bounded. I will discuss some folklore connecting these combinatorial and geometric ideas.