On the difficulty of presenting finitely presentable groups
Group Theory
2011-03-01 v2
Abstract
We exhibit classes of groups in which the word problem is uniformly solvable but in which there is no algorithm that can compute finite presentations for finitely presentable subgroups. Direct products of hyperbolic groups, groups of integer matrices, and right-angled Coxeter groups form such classes. We discuss related classes of groups in which there does exist an algorithm to compute finite presentations for finitely presentable subgroups. We also construct a finitely presented group that has a polynomial Dehn function but in which there is no algorithm to compute the first Betti number of the finitely presentable subgroups.
Cite
@article{arxiv.1003.5117,
title = {On the difficulty of presenting finitely presentable groups},
author = {Martin R Bridson and Henry Wilton},
journal= {arXiv preprint arXiv:1003.5117},
year = {2011}
}
Comments
Final version. To appear in GGD volume dedicated to Fritz Grunewald