Reflection subgroups of odd-angled Coxeter groups
(2014)
Journal Article
Felikson, A., Fintzen, J., & Tumarkin, P. (2014). Reflection subgroups of odd-angled Coxeter groups. Journal of Combinatorial Theory, Series A, 126, 92-127. https://doi.org/10.1016/j.jcta.2014.04.008
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.