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arXiv · 1206.5728

Centralisers of Dehn twist automorphisms of free groups

Moritz Rodenhausen·Richard D. Wade
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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.

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Moritz Rodenhausen, Richard D. Wade. 2014-11-05. Centralisers of Dehn twist automorphisms of free groups. https://doi.org/10.1017/s0305004115000225

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