Geometriae Dedicata

, Volume 117, Issue 1, pp 125–131 | Cite as

On the Residual Finiteness of Outer Automorphisms of Hyperbolic Groups

  • Vassilis Metaftsis
  • Mihalis Sykiotis
Original Article


We show that every virtually torsion-free subgroup of the outer automorphism group of a conjugacy separable hyperbolic group is residually finite. As a result, we are able to prove that the group of outer automorphisms of every finitely generated Fuchsian group and of every free-by-finite group is residually finite.


Hyperbolic groups Residually finite Conjugacy separable Mapping class groups 2-orbifolds Ultralimits of metric spaces 

Mathematics Subject Classifications (2000)

20F67 20E26 20E36 20F28 20E07 57M60 


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Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  1. 1.Department of MathematicsUniversity of the AegeanSamosGreece
  2. 2.M. SykiotisLarissaGreece
  3. 3.Department of Mathematics and StatisticsUniversity of CyprusNicosiaCyprus

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