Centralisers of Dehn twist automorphisms of free groups
Group Theory
2015-05-27 v3 Geometric Topology
Abstract
We refine Cohen and Lustig's description of centralisers of Dehn twists of free groups. We show that the centraliser of a Dehn twist of a free group has a subgroup of finite index that has a finite classifying space. We describe an algorithm to find a presentation of the centraliser. We use this algorithm to give an explicit presentation for the centraliser of a Nielsen automorphism in Aut(F_n). This gives restrictions to actions of Aut(F_n) on CAT(0) spaces.
Cite
@article{arxiv.1206.5728,
title = {Centralisers of Dehn twist automorphisms of free groups},
author = {Moritz Rodenhausen and Richard D. Wade},
journal= {arXiv preprint arXiv:1206.5728},
year = {2015}
}
Comments
33 pages, revised section 5, added section 6.5. Other minor revisions