Hyperbolic hydra

  • Noel Brady

    University of Oklahoma, Norman, United States
  • Will Dison

    Bank of England, London, UK
  • Timothy R. Riley

    Cornell University, Ithaca, USA


We give examples of hyperbolic groups with finite rank free subgroups of huge (Ackermannian) distortion.

Cite this article

Noel Brady, Will Dison, Timothy R. Riley, Hyperbolic hydra. Groups Geom. Dyn. 7 (2013), no. 4, pp. 961–976

DOI 10.4171/GGD/212