Abstract
We construct spanning trees in locally finite hyperbolic graphs that represent their hyperbolic compactification in a good way: so that the tree has at least one but at most a bounded number of disjoint rays to each boundary point. As a corollary we extend a result of Gromov which says that from every hyperbolic graph with bounded degrees one can construct a tree (disjoint from the graph) with a continuous surjection from the ends of the tree onto the hyperbolic boundary such that the surjection is finite-to-one. We shall construct a tree with these properties as a subgraph of the hyperbolic graph, which in addition is also a spanning tree of that graph.
Similar content being viewed by others
References
J. M. Alonso, T. Brady, D. Cooper, V. Ferlini, M. Lustig, M. Mihalik, M. Shapiro and H. Short: Notes on word hyperbolic groups, Group Theory from a Geometrical Viewpoint (Trieste, 1990) (E. Ghys, A. Haeiger, and A. Verjovsky, eds.), World Scientific, 1991, 3–63.
P. Assouad: Plongements lipschitziens dans ℝn, Bull. Soc. Math. France 111 (1983), 429–448.
G. Bell and A. Dranishnikov: Asymptotic dimension, Topology Appl. 155 (dy2008), no. 12, 1265–1296.
I. Benjamini and O. Schramm: Every graph with a positive Cheeger constant contains a tree with a positive Cheeger constant, Geom. Funct. Anal. 7 (1997), 403–419.
M. Bonk and O. Schramm: Embeddings of Gromov hyperbolic spaces, Geom. Funct. Anal. 10 (dy2000), 266–306.
M. Bourdon and H. Pajot: Cohomologie ` p et espace de Besov, J. Reine Angew. Math. 558 (2003), 85–108.
B. H. Bowditch: A Course on Geometric Group Theory, MSJ Memoirs, vol. 16, Mathematical Society of Japan, Tokyo, 2006.
M.R. Bridson and A. Haefliger: Metric spaces of non-positive curvature, Springer-Verlag, 1999.
J. M. Brochet and R. Diestel Normal tree orders for infinite graphs, Trans. Am. Math. Soc. 345 (1995), 871–895.
S. Buyalo, A. Dranishnikov and V. Schroeder: Embedding of hyperbolic groups into products of binary trees, Invent. Math. 169 (2007), 153–192.
S. Buyalo and V. Schroeder: Elements of Asymptotic Geometry, EMS Monographs in Mathematics, EMS, Zürich}, 2007.
M. Coornaert, T. Delzant and A. Papadopoulos: Notes sur les groupes hyperboliques de Gromov, Lecture Notes in Mathematics, vol. 1441, Springer-Verlag, 1990.
M. Coornaert and A. Papadopoulos: Symbolic dynamics and hyperbolic groups, Springer Lecture Notes, vol. 1539, Springer-Verlag, 1993.
R. Diestel: Graph Theory (4th edition), Springer-Verlag, 2010.
G. Elek: The l p-cohomology and the conformal dimension of hyperbolic cones, Geom. Dedicata 68 (1997), 263–279.
E. Ghys and P. de la Harpe: Sur les groupes hyperboliques, d’après M. Gromov, Progress in Math., vol. 83, Birkhäuser, Boston, 1990.
M. Gromov: Hyperbolic Groups, Essays in group theory (S. M. Gersten, ed.), MSRI, vol. 8, Springer, New York, 1987, 75-263.
M. Gromov: Asymptotic invariants of infinite groups, London Math. Soc. Lecture Notes, vol. 182, Cambridge Univ. Press, 1993.
R. Halin: Über unendliche Wege in Graphen, Math. Ann. 157 (1964), 125–137.
I. Holopainen, U. Lang and A. Vähäkangas: Dirichlet problem at infinity on Gromov hyperbolic metric measure spaces, Math. Ann. 339 (2007), 101–134.
H.A. Jung: Wurzelbäume und Kantenorientierungen in Graphen, Math. Nachr. 36 (1968), 351–359.
H.A. Jung: Connectivity in infinite graphs, Studies in Pure Mathematics (L. Mirsky, ed.), Academic Press, 1971, 137–143.
I. Kapovich and N. Benakli: Boundaries of hyperbolic groups, Combinatorial and Geometric Group Theory (R. Gilman et al., ed.), Contemporary Mathematics, vol. 296, 2002, 39–94.
B. Krön and R. G. Möller: Quasi-isometries between graphs and trees, J. Combin. Theory (Series B) 98 (2008), 994–1013.
U. Lang and T. Schlichenmaier: Nagata dimension, quasisymmetric embeddings, and Lipschitz extensions, Int. Math. Res. Not. 58 (2005), 3625–3655.
J. Luukainen: Assouad Dimension: antifractal metrization, Porous sets, and homogeneous measures, J. Korean Math. Soc. 35 (1998), 23–76.
W. Woess: Amenable group actions on infinite graphs, Math. Ann. 284 (1989), 251–265.
W. Woess: Random walks on infinite graphs and groups, Cambridge University Press, 2000.