English

Weyl Groups with Coxeter Presentation and Presentation by Conjugation

Group Theory 2007-05-23 v1

Abstract

We investigate which Weyl groups have a Coxeter presentation and which of them at least have the presentation by conjugation with respect to their root system. For most concepts of root systems the Weyl group has both. In the context of extended affine root systems (EARS) there is a small subclass allowing a Coxeter presentation of the Weyl group and a larger subclass allowing the presentation by conjugation. We give necessary and sufficient conditions for both classes. Our results entail that every extended affine Weyl group (EAWeG) has the presentation by conjugation with respect to a suitable EARS.

Keywords

Cite

@article{arxiv.math/0607562,
  title  = {Weyl Groups with Coxeter Presentation and Presentation by Conjugation},
  author = {Georg Hofmann},
  journal= {arXiv preprint arXiv:math/0607562},
  year   = {2007}
}

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23 pages