## Illinois Journal of Mathematics

#### Abstract

The goal of this paper is to introduce a new tool, called long turns, which is a useful addition to the train track technology for automorphisms of free groups, in that it allows one to control periodic INPs in a train track map and hence the index of the induced automorphism.

#### Article information

Source
Illinois J. Math., Volume 59, Number 4 (2015), 1087-1109.

Dates
Revised: 12 May 2016
First available in Project Euclid: 27 February 2017

https://projecteuclid.org/euclid.ijm/1488186022

Digital Object Identifier
doi:10.1215/ijm/1488186022

Mathematical Reviews number (MathSciNet)
MR3628302

Zentralblatt MATH identifier
1382.20029

#### Citation

Coulbois, Thierry; Lustig, Martin. Long turns, INP’s and indices for free group automorphisms. Illinois J. Math. 59 (2015), no. 4, 1087--1109. doi:10.1215/ijm/1488186022. https://projecteuclid.org/euclid.ijm/1488186022

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