English

Bounded cohomology and isometry groups of hyperbolic spaces

Group Theory 2007-05-23 v4 Dynamical Systems

Abstract

Let X be an arbitrary hyperbolic geodesic metric space and let G be a countable non-elementary weakly acylindrical group of isometries of X. We show that the second bounded cohomology group of G with real coefficients or with coefficients in the regular representation is infinite dimensional. The result holds for any subgroup of the mapping class group of a non-exceptional surface of finite type not containing a normal subgroup which virtually split as a direct product.

Keywords

Cite

@article{arxiv.math/0507097,
  title  = {Bounded cohomology and isometry groups of hyperbolic spaces},
  author = {Ursula Hamenstaedt},
  journal= {arXiv preprint arXiv:math/0507097},
  year   = {2007}
}

Comments

36 pages; Corollary 4.5 corrected, writing improved

R2 v1 2026-07-22T17:21:42.205Z