SMS scnews item created by Bill Unger at Thu 7 Apr 2011 1742
Type: Seminar
Distribution: World
Expiry: 14 Apr 2011
Calendar1: 14 Apr 2011 1505-1600
CalLoc1: Carslaw 535A
Auth: billu@daumier.maths.usyd.edu.au

# Computational Algebra Seminar: de Graaf -- Classifying semisimple orbits of theta-groups

Speaker: Willem de Graaf
Title: Classifying semisimple orbits of theta-groups
Time & Place: 3:05-4pm, Thursday 14 April, Carslaw 535

Abstract:
Theta-groups were introduced by Vinberg in the 70-s.
They are a class of reductive algebraic groups for which
there is a well-developed theory dealing with their orbits,
allowing classifications of them. In this talk I will describe what
theta-groups are, and then concentrate on the semisimple
orbits. Vinberg showed that every semisimple orbit has a
point in a subspace called Cartan subspace, two points
of a Cartan subspace are conjugate iff they are conjugate
under a certain complex reflection group, called the
little Weyl group, and different orbits of the little Weyl group
are separated by invariants. I will describe some computational
techniques for computing a Cartan subspace and the little
Weyl group, and the results obtained with them, using Magma.


If you are registered you may mark the scnews item as read.
School members may try to .