Abstract
We prove that for every finitely generated hyperbolic group G, the action of G on its Gromov boundary induces a hyperfinite equivalence relation.
Similar content being viewed by others
References
Abramenko, P., Brown, K.S.: Buildings, Graduate Texts in Mathematics, vol. 248. Springer, New York (2008). Theory and applications
Adams, S.: Boundary amenability for word hyperbolic groups and an application to smooth dynamics of simple groups. Topology 33(4), 765–783 (1994)
Bridson, M.R., Haefliger, A.: Metric spaces of non-positive curvature, Grundlehren der Mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], vol. 319. Springer, Berlin (1999)
Connes, A., Feldman, J., Weiss, B.: An amenable equivalence relation is generated by a single transformation. Ergod. Theory Dyn. Syst. 1(4), 431–450 (1982)
Caprace, P.-E., Lécureux, J.: Combinatorial and group-theoretic compactifications of buildings. Ann. Inst. Fourier Grenoble 61(2), 619–672 (2011)
Dougherty, R., Jackson, S., Kechris, A.S.: The structure of hyperfinite Borel equivalence relations. Trans. Am. Math. Soc. 341(1), 193–225 (1994)
Gao, S.: Invariant descriptive set theory, Pure and Applied Mathematics (Boca Raton), vol. 293. CRC Press, Boca Raton (2009)
Gromov, M.: Hyperbolic groups, Essays in group theory, Math. Sci. Res. Inst. Publ., vol. 8. Springer, New York, pp. 75–263 (1987)
Huang, J., Sabok, M., Shinko, F.: Hyperfiniteness of boundary actions of cubulated hyperbolic groups. Ergod. Theory Dyn. Syst. (2019). https://doi.org/10.1017/etds.2019.5
Kanovei, V.: Borel Equivalence Relations, University Lecture Series, vol. 44. American Mathematical Society, Providence (2008). Structure and classification
Kechris, A.S.: Classical descriptive set theory, Graduate Texts in Mathematics, vol. 156. Springer, New York (1995)
Marquis, T.: On geodesic ray bundles in buildings. Geom. Dedicata, 1–17 (2018). https://doi.org/10.1007/s10711-018-0401-y
Slaman, T.A., Steel, J.R.: Definable functions on degrees, Cabal Seminar 81–85, Lecture Notes in Math., vol. 1333. Springer, Berlin, pp. 37–55 (1988)
Touikan, N.: On geodesic ray bundles in hyperbolic groups. Proc. Am. Math. Soc. 146(10), 4165–4173 (2018)
Vershik, A.M.: The action of \({\rm PSL}(2, {\mathbf{Z}})\) in \({\mathbf{R}}^{1}\) is approximable. Uspehi Mat. Nauk 33(1(199)), 209–210 (1978)
Weiss, B.: Measurable dynamics, Conference in modern analysis and probability (New Haven, Conn., 1982), Contemp. Math., vol. 26. Amer. Math. Soc., Providence, pp. 395–421 (1984)
Acknowledgements
We would like to thank the referee for many valuable comments.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Andreas Thom.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
T. Marquis was F.R.S.-FNRS Postdoctoral Researcher. M. Sabok: This research was partially supported by the NSERC through the Discovery Grant RGPIN-2015-03738, by the FRQNT (Fonds de recherche du Québec) grant Nouveaux chercheurs 2018-NC-205427 and by the NCN (National Science Centre, Poland) through the grants Harmonia no. 2015/18/M/ST1/00050 and 2018/30/M/ST1/00668.
Rights and permissions
About this article
Cite this article
Marquis, T., Sabok, M. Hyperfiniteness of boundary actions of hyperbolic groups. Math. Ann. 377, 1129–1153 (2020). https://doi.org/10.1007/s00208-020-02001-9
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00208-020-02001-9