English

Lifting of elements of Weyl groups

Representation Theory 2016-08-02 v1

Abstract

Suppose GG is a reductive algebraic group, TT is a Cartan subgroup, N=Norm(T)N=\text{Norm}(T), and W=N/TW=N/T is the Weyl group. If wWw\in W has order dd, it is natural to ask about the orders lifts of ww to NN. It is straightforward to see that the minimal order of a lift of ww has order dd or 2d2d, but it can be a subtle question which holds. We first consider the question of when WW itself lifts to a subgroup of NN (in which case every element of WW lifts to an element of NN of the same order). We then consider two natural classes of elements: regular and elliptic. In the latter case all lifts of ww are conjugate, and therefore have the same order. We also consider the twisted case.

Keywords

Cite

@article{arxiv.1608.00510,
  title  = {Lifting of elements of Weyl groups},
  author = {Jeffrey Adams and Xuhua He},
  journal= {arXiv preprint arXiv:1608.00510},
  year   = {2016}
}
R2 v1 2026-06-22T15:09:18.299Z