Jon F Carlson, Nadia Mazza, Daniel K Nakano
Endotrivial modules for finite groups of Lie type
1. Introduction
Let G be a finite group and k be a field of characteristic p
> 0. An endotrivial kG-module is a finitely generated kG-module
M whose k-endomorphism ring is isomorphic to a trivial module in the stable
module category. That is, M is an endotrivial module provided
where P is a projective
kG-module. Now recall that as kG-modules,
where M
* = Homk (M, k) is the k-dual of M.
Hence, the functor “
” induces an equivalence on the
stable module category and the collection of all endotrivial modules makes up a part of the Picard group of all stable
equivalences of kG-modules. In particular, equivalence classes of endotrivial modules modulo projective
summands form a group that is an essential part of the group of stable self-equivalences.
Journal fur die reine und angewandte Mathematik (Crelles Journal), Walter de Gruyter
Print ISSN: 0075-4102
Volume: 2006, 06/2006
Pages: 93 - 119
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