On reflection subgroups of finite Coxeter groups
arXiv:1101.5893
Abstract
Let be a finite Coxeter group. We classify the reflection subgroups of up to conjugacy and give necessary and sufficient conditions for the map that assigns to a reflection subgroup of the conjugacy class of its Coxeter elements to be injective, up to conjugacy.
17 pages; final version, to appear in Comm. Algebra