Weyl Groups with Coxeter Presentation and Presentation by Conjugation
Journal of Lie Theory, Volume 17 (2007) no. 2, pp. 337-355
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.
DOI: 10.5802/jolt.450
Classification: 20F55, 17B65, 17B67, 22E65
Keywords: Weyl group, Coxeter group, root system, presentation of a group, presentation by conjugation, extended affine Weyl group (EAWeG), extended affine root system (EARS)
@article{JOLT_2007_17_2_a6,
     author = {G. W. Hofmann},
     title = {Weyl {Groups} with {Coxeter} {Presentation} and {Presentation} by {Conjugation}},
     journal = {Journal of Lie Theory},
     pages = {337--355},
     year = {2007},
     volume = {17},
     number = {2},
     doi = {10.5802/jolt.450},
     zbl = {1144.20021},
     url = {https://jolt.centre-mersenne.org/articles/10.5802/jolt.450/}
}
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G. W. Hofmann. Weyl Groups with Coxeter Presentation and Presentation by Conjugation. Journal of Lie Theory, Volume 17 (2007) no. 2, pp. 337-355. doi: 10.5802/jolt.450

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