This is a reminder for  the Bellingham Algebraic Geometry Seminar
Saturday, Nov. 6 at Western  Washington U. The talks will be held
in Bond Hall (the usual place). The full schedule with abstracts
is on Sandor Kovacs's webpage

http://www.math.washington.edu/~kovacs/pnw_ags

The schedule is as follows:

11:30
Nikos Tziolas: Three dimensional divisoral extremal neighborhoods

2:30
Angela Gibney: A higher dimensional analogue of the moduli space of
pointed stable curves

3:45
Allen Knutson: Path models for T-varieties with isolated fixed points

5:00 Dinner

Also, don't forget that Knutson is giving the colloquium at UBC
on Friday (the 5th) at 3:00.


Knutson's abstract is below:

Let X be a projective variety carrying a torus action with isolated
fixed points -- for example a toric variety, flag manifold, Hilbert scheme
of n points in the plane, etc. I'll show how to flatly degenerate X
to a union of (abnormal) toric varieties, while keeping it reduced
and the combinatorics under control (in particular, no new fixed points).
The main ingredients are the Bialynicki-Birula decomposition and the
(frightfully underexploited) Samuel-Rees filtrations.

This degeneration gives a positive formula for the (equivariant) degree of X,
and an upper bound on the Hilbert function. In the case of a flag manifold,
this upper bound is achieved, and is the Littelmann path model formula
for weight multiplicities of representations. (It's also achieved for toric
varieties, but boring.) For most of the other examples it seems to be new.

Ann Artuso
Manuscript/Resource Secretary
Department of Mathematics
The University of British Columbia
Telephone: 3-0901, (604) 822-2666
email: artuso@math.ubc.ca

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Last updated 30 October, 2004