Speaker:

Peter Symonds

(Manchester)

Date/Time:

Mon, 26/10/2009 - 16:30

Room:

M103

Seminar series:

We show that, when a group acts on a polynomial ring over a field, the ring of invariants has Castelnuovo-Mumford regularity at most zero. As a consequence, we prove a well-known conjecture that the invariants are always generated in degrees at most n(|G|-1), where n >1 is the number of polynomial generators and |G|>1 is the order of the group.

The proof is a mixture of commutative algebra and representation theory.