Hyperbolic Coxeter groups of minimal growth rates in higher dimensions

On the growth of cocompact hyperbolic Coxeter groups

For an arbitrary cocompact hyperbolic Coxeter group G with finite generator set S and complete growth function fS(x) = P (x)/Q(x) , we provide a recursion formula for the coefficients of the denominator polynomial Q(x). It allows to determine recursively the Taylor coefficients and to study the arithmetic nature of the poles of the growth function fS(x) in terms of its subgroups and exponent va...

Coxeter Groups and Hyperbolic Manifolds

In the last quarter of a century, 3-manifold topology has been revolutionized by Thurston and his school. This has generated a huge literature on hyperbolic 3-manifolds, building on the classical body of knowledge already existing in 2-dimensions. Balanced against this is a relative paucity of techniques and examples of hyperbolic n-manifolds for n ≥ 4. Recent work of Ratcliffe and Tschantz has...

On Subgroup Separability in Hyperbolic Coxeter Groups

On Subgroup Separability in Hyperbolic Coxeter Groups

We prove that certain hyperbolic Coxeter groups are separable on their geometrically ¢nite subgroups. Mathematics Subject Classi¢cation (2000). 20H10. Key words. hyperbolic Coxeter group, subgroup separability. 1. Introduction Recall that a subgroupH of a group G is separable in G if, given any g 2 G nH, there exists a subgroup K < G of ¢nite index with H < K and g = 2K . G is called subgroup s...

Computation in Coxeter Groups Ii. Minimal Roots

In the recent paper (Casselman, 2001) I described how a number of ideas due to Fokko du Cloux and myself could be incorporated into a reasonably efficient program to carry out multiplication in arbitrary Coxeter groups. At the end of that paper I discussed how this algorithm could be used to build the reflection table of minimal roots, which could in turn form the basis of a much more efficient...