We give a criterion for a finitely generated odd-angled Coxeter group to have a proper finite index subgroup generated by reflections. The answer is given in terms of the least prime divisors of the exponents of the Coxeter relations.
Coxeter group, Reflection subgroup, Davis complex.
Accepted Journal Article
NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Combinatorial Theory, Series A. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Combinatorial Theory, Series A, 126, 2014, 10.1016/j.jcta.2014.04.008.