# What is a good quotient?

**Date**: Thursday 19 October 2017, 16:15 – 17:15**Location**: Mathematics Level 8, MALL 1 & 2, School of Mathematics**Type**: Seminars, Pure Mathematics**Cost**: Free

#### Part of the pure mathematics pure postgraduate seminar series.

When an algebraic group is acting on a variety, we would like to know if there exists a variety structure on the set of orbits. However it is easy to find counter-examples, so we need to find a natural space to replace the ill-behaved space of orbits. I will explain how such a categorical quotient can be realised in the context of (affine) Geometric Invariant Theory, using GIT quotients. Some basic knowledge of algebraic geometry is welcome.

*Attendees meet at 2:40pm in the Mathematics Common Room for tea and biscuits. The current seminar organisers are Joe Oliver and Amit Shah. *

**Maxime Fairon **