Abstract
We prove a general version of the amenability conjecture in the unified setting of a Gromov hyperbolic group G acting properly cocompactly either on its Cayley graph, or on a CAT(-1)-space. Namely, for any subgroup H of G, we show that H is co-amenable in G if and only if their exponential growth rates (with respect to the prescribed action) coincide. For this, we prove a quantified, representation-theoretical version of Stadlbauer’s amenability criterion for group extensions of a topologically transitive subshift of finite type, in terms of the spectral radii of the classical Ruelle transfer operator and its corresponding extension. As a consequence, we are able to show that, in our enlarged context, there is a gap between the exponential growth rate of a group with Kazhdan’s property (T) and the ones of its infinite index subgroups. This also generalizes a well-known theorem of Corlette for lattices of the quaternionic hyperbolic space or the Cayley hyperbolic plane.
Similar content being viewed by others
References
Baladi V.: Positive transfer operators and decay of correlations, volume 16 of Advanced Series in Nonlinear Dynamics. World Scientific Publishing Co.Inc., River Edge, NJ (2000)
Ballmann W.: Lectures on spaces of nonpositive curvature, volume 25 of DMV Seminar. Birkhäuser Verlag, Basel (1995)
Bekka M.E.B., de la Harpe P., Valette A.: Kazhdan’s property (T), volume 11 of New Mathematical Monographs. Cambridge University Press, Cambridge (2008)
Bourbaki N.: Éléments de mathématique Topologie générale. Chapitres 1 à 4. Hermann, Paris (1971)
Brooks. R., The fundamental group and the spectrum of the Laplacian. Commentarii Mathematici Helvetici, 56(4), 581–598 (1981)
Brooks. R. The bottom of the spectrum of a Riemannian covering. Journal für die Reine und Angewandte Mathematik. [Crelle’s Journal], 357(357), 101–114 (1985)
Burger M.: Spectre du laplacien, graphes et topologie de Fell. Commentarii Mathematici Helvetici, 63(2), 226–252 (1988)
Champetier C.: Petite simplification dans les groupes hyperboliques. Toulouse. Facultédes Sciences. Annales. Mathématiques. Série 6, 3(2), 161–221 (1994)
Cohen J.M.: Cogrowth and amenability of discrete groups. Journal of Functional Analysis, 48(3) 301–309 (1982)
D. Constantine, J.-F. Lafont, and D. Thompson. The weak specification property for geodesic flows on CAT(-1) spaces. arXiv.org, (June 2016).
Conway J.B.: A course in functional analysis, volume 96 of Graduate Texts in Mathematics. Springer-Verlag, New York (1985)
Coornaert M.: Mesures de Patterson-Sullivan sur le bord d’un espace hyperbolique au sens de Gromov. Pacific Journal of Mathematics, 159(2), 241–270 (1993)
Coornaert M., Delzant T., Papadopoulos A.: Géométrie et théorie des groupes, volume 1441 of Lecture Notes in Mathematics. Springer-Verlag, Berlin (1990)
Coornaert M., Papadopoulos A.: Symbolic dynamics and hyperbolic groups, volume 1539 of Lecture Notes in Mathematics. Springer–Verlag, Berlin (1993)
Coornaert M., Papadopoulos A.: Horofunctions and symbolic dynamics on Gromov hyperbolic groups. Glasgow Mathematical Journal, 43(3), 425–456 (2001)
Coornaert M., Papadopoulos A.: Symbolic coding for the geodesic flow associated to a word hyperbolic group. Manuscripta Mathematica 109(4), 465–492 (2002)
Corlette. K.Hausdorff dimensions of limit sets. I. Inventiones Mathematicae, 102(3) 521–541 (1990)
Dal’Bo F.: Geodesic and horocyclic trajectories. Universitext. Springer-Verlag London, Ltd. (2011) EDP Sciences, Les Ulis, London
Dal’Bo F., Otal J.-P., Peigné M.: Séries de Poincaré des groupes géométriquement finis. Israel Journal of Mathematics, 118(1), 109–124 (2000)
Dal’Bo F., M. , Peigné M., Picaud J.-C., Sambusetti A.: Convergence and counting in infinite measure. Université de Grenoble. Annales de l’Institut Fourier, 67(2), 483–520 (2017)
R. Dougall. Critical exponents of normal subgroups, the spectrum of group extended transfer operators, and Kazhdan distance. arXiv.org, (Feb. 2017).
R. Dougall and R. Sharp. Amenability, critical exponents of subgroups and growth of closed Geodesics. Mathematische Annalen. (3–4)365 (2016), 1359–1377.
Fisher D., Margulis G.: Almost isometric actions, property (T), and local rigidity. Inventiones Mathematicae, 162(1), 19–80 (2005)
R.I. Grigorchuk. Symmetrical random walks on discrete groups. In Multicomponent random systems, pages 285–325. Dekker, New York, (1980).
M. Gromov. Hyperbolic groups. In Math. Sci. Res. Inst. Publ., pages 75–263. Springer, New York, (1987).
Hennion H., Hervé L.: Limit theorems for Markov chains and stochastic properties of dynamical systems by quasi-compactness, volume 1766 of Lecture Notes in Mathematics. Springer-Verlag, Berlin (2001)
Jaerisch J.: Group-extended Markov systems, amenability, and the Perron- Frobenius operator. Proceedings of the American Mathematical Society, 143(1), 289–300 (2015)
Kesten H.: Full Banach mean values on countable groups. Mathematica Scandinavica, 7, 146–156 (1959)
Margulis G.A.: On the decomposition of discrete subgroups into amalgams. Selecta Mathematica Sovietica, 1(2), 197–213 (1981)
F. Mathéus. Flot géodésique et groupes hyperboliques d’après M. Gromov. In S éminaire de Théorie Spectrale et Géométrie, No. 9, Année 1990–1991, pages 67–87. Univ. Grenoble I, Saint-Martin-d’Hères, (1991).
Neumann B.H.: Groups covered by finitely many cosets. Publicationes Mathematicae Debrecen 3, 227–242 (1955) 1954.
Paulin F.: Un groupe hyperbolique est déterminé par son bord. Journal of the London Mathematical Society. Second Series, 54(1), 50–74 (1996)
Paulin F.: On the critical exponent of a discrete group of hyperbolic isometries. Differential Geometry and its Applications, 7(3), 231–236 (1997)
Roblin T.: Un théorème de Fatou pour les densités conformes avec applications aux revêtements galoisiens en courbure négative. Israel Journal of Mathematics, 147(1), 333–357 (2005)
T. Roblin and S. Tapie. Exposants critiques et moyennabilité. In Géométrie ergodique, pages 61–92. Enseignement Math., Geneva, Hoboken, NJ, USA, (2013).
Stadlbauer M.: An extension of Kesten’s criterion for amenability to topological Markov chains. Advances in Mathematics, 235, 450–468 (2013)
Tukia P.: Convergence groups and Gromov’s metric hyperbolic spaces. New Zealand Journal of Mathematics, 23(2), 157–187 (1994)
Watatani Y.: Property T of Kazhdan implies property FA of Serre. Mathematica Japonica, 27(1), 97–103 (1982)
Woess W.: Random walks on infinite graphs and groups, volume 138 of Cambridge Tracts in Mathematics. Cambridge University Press, Cambridge (2000)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Coulon, R., Dal’Bo, F. & Sambusetti, A. Growth gap in hyperbolic groups and amenability. Geom. Funct. Anal. 28, 1260–1320 (2018). https://doi.org/10.1007/s00039-018-0459-6
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00039-018-0459-6