Geometric and Functional Analysis

, Volume 20, Issue 3, pp 657–689 | Cite as

Twisting Out Fully Irreducible Automorphisms



By a theorem of Thurston, in the subgroup of the mapping class group generated by Dehn twists around two curves which fill, every element not conjugate to a power of one of the twists is pseudo-Anosov. We prove an analogue of this theorem for the outer automorphism group of a free group.

Keywords and phrases

Free group automorphism Dehn twist pseudo-Anosov 

2010 Mathematics Subject Classification

20F65 20E36 20E05 


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Copyright information

© Springer Basel AG 2010

Authors and Affiliations

  1. 1.Dept. of MathematicsAllegheny CollegeMeadvilleUSA
  2. 2.Dept. of MathematicsUniversity of MichiganAnn ArborUSA

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