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CATEGORIES:Algebraic Geometry Seminar
SUMMARY:The Slice Method for torsors of algebraic groups -
Mark MacDonald (Lancaster)
DTSTART;TZID=Europe/London:20131113T141500
DTEND;TZID=Europe/London:20131113T151500
UID:TALK46584AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/46584
DESCRIPTION:Given a linear representation V of a linear algebr
aic group G\, the slice method in invariant theory
is a way of reducing birationality questions abou
t V/G to questions about S/N(S)\, where S < V is a
"slice"\, and N(S) is its normalizer. I will desc
ribe how an analogous method could be applied to G
-torsors over a field\, to obtain a reduction to N
(S)-torsors. This leads to new information about e
ssential dimension. In this talk I will also give
some context for the notion of essential dimension
\, and finally I will explain the various ways the
slice method can be applied when G is the split e
xceptional algebraic group of type F_4\, hence giv
ing new bounds on ed(F_4). \n
LOCATION:MR 13\, CMS
CONTACT:Dr. J Ross
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