Transformation Groups

, Volume 10, Issue 3, pp 449–487

Unipotent elements in small characteristic


DOI: 10.1007/s00031-005-0405-1

Cite this article as:
Lusztig, G. Transformation Groups (2005) 10: 449. doi:10.1007/s00031-005-0405-1


Let G be a reductive connected algebraic group over an algebraically closed field of characteristic exponent p ≥ 1. One of the aims of this paper is to present a picture of the unipotent elements of G which should apply for arbitrary p and is as close as possible to the picture for p = 1. Another aim is the study of Bu, the variety of Borel subgroups of G containing a unipotent element u. It is known [Sp] that when p is a good prime, the l-adic cohomology spaces of Bu are pure. We would like to prove a similar result in the case where p is a bad prime. We present a method by which this can be achieved in a number of cases.

Copyright information

© Birkhauser Boston 2005

Authors and Affiliations

  1. 1.Department of Mathematics, MIT, Cambridge, MA 02139USA

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