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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Between the sheets: rigid nilpotent elements in mo
dular Lie algebras - David Stewart (University of
Newcastle upon Tyne)
DTSTART;TZID=Europe/London:20200128T144500
DTEND;TZID=Europe/London:20200128T153500
UID:TALK137908AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/137908
DESCRIPTION:(Joint with Sasha Premet) Let G be a reductive alg
ebraic group over an algebraically closed field. L
usztig and Spaltenstein provided a method for indu
cing a nilpotent orbit from a Levi subgroup to the
group G. Any orbit not obtained from a proper Lev
i subgroup is called rigid. These were classified
by Kempken (for G classical) and Elashvili (for G
exceptional). The latter was double-checked comput
ationally by De Graaf. It turns out that this clas
sification remains valid in characteristic p. I wi
ll explain the proof of this\, obtained by extendi
ng the Borho-Kraft description of the sheets of th
e Lie algebra to positive characteristic and suppo
rted by a few computer calculations.
LOCATION:Seminar Room 1\, Newton Institute
CONTACT:info@newton.ac.uk
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