Virtually special non-finitely presented groups via linear characters

Finitely Presented Residually Free Groups

We establish a general criterion for the finite presentability of subdirect products of groups and use this to characterize finitely presented residually free groups. We prove that, for all n ∈ N, a residually free group is of type FPn if and only if it is of type Fn. New families of subdirect products of free groups are constructed, including the first examples of finitely presented subgroups ...

Coxeter groups are virtually special

In this paper we prove that every finitely generated Coxeter group has a finite index subgroup that is the fundamental group of a special cube complex. Some consequences include: Every f.g. Coxeter group is virtually a subgroup of a right-angled Coxeter group. Every word-hyperbolic Coxeter group has separable quasiconvex subgroups. © 2010 Elsevier Inc. All rights reserved. MSC: 53C23; 20F36; 20...

Non-amenable finitely presented torsion-by-cyclic groups

We construct a finitely presented non-amenable group without free non-cyclic subgroups thus providing a finitely presented counterexample to von Neumann’s problem. Our group is an extension of a group of finite exponent n >> 1 by a cyclic group, so it satisfies the identity [x, y] = 1.

Non-amenable Finitely Presented Torsion-by-cyclic Groups

We construct a finitely presented non-amenable group without free non-cyclic subgroups thus providing a finitely presented counterexample to von Neumann’s problem. Our group is an extension of a group of finite exponent n 1 by a cyclic group, so it satisfies the identity [x, y]n = 1. 1. Short history of the problem Hausdorff [14] proved in 1914 that one can subdivide the 2-sphere minus a counta...

On the Restriction of Characters of Special Linear Groups of Dimension Three