PreprintarXiv licencearXiv
Prefixes of Coxeter elements are Coxeter elements of the reflection subgroups they generate
Abstract
Let (W,S) be a Coxeter system of finite rank, let T be its set of reflections and let c ∈ W be a Coxeter element. For x in the interval [1,c]T of the absolute order, let P(x) be the subgroup generated by the reflections t≤T x. We prove that x is a Coxeter element of P(x) with respect to the canonical Coxeter generators of P(x), that P(x) is generated by the factors of any reduced reflection factorization of x, and that the Hurwitz action on the reduced reflection factorizations of x is transitive. The proof reduces the general case to the case of a Coxeter system whose Coxeter matrix has entries in {1,2,3,∞}, which was treated by Hubery and Krause.
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BibTeX
@misc{wegener2026prefixes,
title = {{Prefixes of Coxeter elements are Coxeter elements of the reflection subgroups they generate}},
author = {Patrick Wegener},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.19755},
eprint = {2610.19755},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.19755},
}
RIS
TY - UNPB
TI - Prefixes of Coxeter elements are Coxeter elements of the reflection subgroups they generate
AU - Patrick Wegener
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.19755
UR - https://arxiv.org/abs/2610.19755
AB - Let (W,S) be a Coxeter system of finite rank, let T be its set of reflections and let c ∈ W be a Coxeter element. For x in the interval [1,c]_T of the absolute order, let P(x) be the subgroup generated by the reflections t≤_T x. We prove that x is a Coxeter element of P(x) with respect to the canonical Coxeter generators of P(x), that P(x) is generated by the factors of any reduced reflection factorization of x, and that the Hurwitz action on the reduced reflection factorizations of x is transitive. The proof reduces the general case to the case of a Coxeter system whose Coxeter matrix has entries in {1,2,3,∞}, which was treated by Hubery and Krause.
ER -