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We study the geometry of nonrelatively hyperbolic groups. Generalizing a result of Schwartz, any quasi-isometric image of a non-relatively hyperbolic space in a relatively hyperbolic space is contained in a bounded neighborhood of a single…

Geometric Topology · Mathematics 2010-04-13 Jason Behrstock , Cornelia Drutu , Lee Mosher

This paper is devoted to study of transformations on metric spaces. It is done in an effort to produce qualitative version of quasi-isometries which takes into account the asymptotic behavior of the Gromov product in hyperbolic spaces. We…

Metric Geometry · Mathematics 2015-07-28 Hideki Miyachi

Given a closed surface $S$ with finitely generated Veech group $G$ and its $\pi_1(S)$-extension $\Gamma$, there exists a hyperbolic space $\hat{E}$ on which $\Gamma$ acts isometrically and cocompactly. The space $\hat{E}$ is obtained by…

Geometric Topology · Mathematics 2026-04-08 Eliot Bongiovanni

In the context of CAT(0) cubical groups, we develop an analogue of the theory of curve complexes and subsurface projections. The role of the subsurfaces is played by a collection of convex subcomplexes called a \emph{factor system}, and the…

Geometric Topology · Mathematics 2017-06-14 Jason Behrstock , Mark F. Hagen , Alessandro Sisto

We prove that the hierarchical hull of any finite set of interior points, hierarchy rays, and boundary points in a hierarchically hyperbolic space (HHS) is quasi-median quasi-isometric to a CAT(0) cube complex of bounded dimension. Our…

Group Theory · Mathematics 2023-08-29 Matthew Gentry Durham

In this paper, we classify completely hyperbolic 3-manifolds corresponding to geometric limits of Kleinian surface groups isomorphic to $\pi_1(S)$ for a finite-type hyperbolic surface $S$. In the first of the three main theorems, we…

Geometric Topology · Mathematics 2015-05-22 Ken'ichi Ohshika , Teruhiko Soma

The boundary $\partial X$ of a boundary continuous Gromov hyperbolic space $X$ carries a natural Moebius structure on the boundary. For a proper, geodesically complete, boundary continuous Gromov hyperbolic space $X$, the boundary $\partial…

Metric Geometry · Mathematics 2025-10-30 Kingshook Biswas , Arkajit Pal Choudhury

We investigate the relationship between the metric boundary and the Gromov boundary of a hyperbolic metric space. We show that the Gromov boundary is a quotient topological space of the metric boundary, and that therefore a word-hyperbolic…

Metric Geometry · Mathematics 2007-05-23 Corran Webster , Adam Winchester

We introduce a construction that simultaneously yields cusped spaces of relatively hyperbolic groups, and spaces quasi-isometric to Teichmueller metrics. We use this to study Dehn-filling-like quotients of various groups, among which…

Geometric Topology · Mathematics 2026-04-16 Giorgio Mangioni , Alessandro Sisto

Hierarchically hyperbolic spaces (HHSs) are a large class of spaces that provide a unified framework for studying the mapping class group, right-angled Artin and Coxeter groups, and many 3--manifold groups. We investigate strongly…

Group Theory · Mathematics 2021-06-18 Jacob Russell , Davide Spriano , Hung Cong Tran

In this article we prove that the set of torsion-free groups acting by isometries on a hyperbolic metric space whose entropy is bounded above and with a compact quotient is finite. The number of such groups can be estimated in terms of the…

Group Theory · Mathematics 2021-11-09 Gérard Besson , Gilles Courtois , Sylvestre Gallot , Andrea Sambusetti

For an infinite type surface $\Sigma$, we consider the space of (marked) convex hyperbolic structures on $\Sigma$, denoted $H(\Sigma)$, with the Fenchel-Nielsen topology. The (big) mapping class group acts faithfully on this space allowing…

Geometric Topology · Mathematics 2024-10-10 Ara Basmajian , Yassin Chandran

For any intrinsic Gromov hyperbolic space we establish a Gehring-Hayman type theorem for conformally deformed spaces. As an application, we prove that any complete intrinsic hyperbolic space with atleast two points in the Gromov boundary…

Complex Variables · Mathematics 2024-11-04 Vasudevarao Allu , Alan P Jose

We provide sufficient conditions for two subgroups of a hierarchically hyperbolic group to generate an amalgamated free product over their intersection. The result applies in particular to certain geometric subgroups of mapping class groups…

Group Theory · Mathematics 2026-01-07 Giorgio Mangioni

We study $2$-dimensional Artin groups of hyperbolic type from the viewpoint of measure equivalence, and establish rigidity theorems. We first prove that they are boundary amenable. So is every group acting discretely by simplicial…

Group Theory · Mathematics 2021-10-11 Camille Horbez , Jingyin Huang

We introduce the co-surface graph $\mathcal{CS}$ of a finitely generated free group $\mathbb{F}$ and use it to study the geometry of hyperbolic group extensions of $\mathbb{F}$. Among other things, we show that the Gromov boundary of the…

Geometric Topology · Mathematics 2017-05-04 Spencer Dowdall , Samuel J. Taylor

The mapping class group of a surface with one boundary component admits numerous interesting representations including as a group of automorphisms of a free group and as a group of symplectic transformations. Insofar as the mapping class…

Geometric Topology · Mathematics 2009-06-01 Jorgen Ellegaard Andersen , Alex James Bene , R. C. Penner

The class of coarsely convex spaces is a coarse geometric analogue of the class of nonpositively curved Riemannian manifolds. It includes Gromov hyperbolic spaces, CAT(0) spaces, proper injective metric spaces and systolic complexes. It is…

Metric Geometry · Mathematics 2024-02-20 Yuuhei Ezawa , Tomohiro Fukaya

We prove that the Gromov boundary of every hyperbolic group is homeomorphic to some Markov compactum. Our reasoning is based on constructing a sequence of covers of $\partial G$, which is quasi-$G$-invariant wrt. the ball $N$-type (defined…

Geometric Topology · Mathematics 2015-03-17 Dominika Pawlik

In this article, we study acylindrical graphs of groups, local quasiconvexity, and Cannon-Thurston maps in the setting of totally disconnected locally compact (TDLC) hyperbolic groups, extending several fundamental notions and results from…

Group Theory · Mathematics 2026-01-28 Swarnali Datta , Arunava Mandal , Ravi Tomar