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Related papers: Stability and the Morse boundary

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In the spirit of peripheral subgroups in relatively hyperbolic groups, we exhibit a simple class of quasi-isometrically rigid subgroups in graph products of finite groups, which we call eccentric subgroups. As an application, we prove that,…

Group Theory · Mathematics 2022-08-10 Anthony Genevois

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

Hierarchically hyperbolic spaces provide a common framework for studying mapping class groups of finite type surfaces, Teichm\"uller space, right-angled Artin groups, and many other cubical groups. Given such a space $\mathcal X$, we build…

Geometric Topology · Mathematics 2018-03-16 Matthew G. Durham , Mark F. Hagen , Alessandro Sisto

We show that the Morse boundary of a Morse local-to-global group is $\sigma$-compact. Moreover, we show that the converse holds for small cancellation groups. As an application, we show that the Morse boundary of a non-hyperbolic, Morse…

Group Theory · Mathematics 2024-07-29 Vivian He , Davide Spriano , Stefanie Zbinden

In this paper we obtain uniform positive lower bounds on stable commutator length in word-hyperbolic groups and certain groups acting on hyperbolic spaces (namely the mapping class group acting on the complex of curves, and an amalgamated…

Group Theory · Mathematics 2009-12-06 Danny Calegari , Koji Fujiwara

The Morse boundary of a proper geodesic metric space is designed to encode hypberbolic-like behavior in the space. A key property of this boundary is that a quasi-isometry between two such spaces induces a homeomorphism on their Morse…

Geometric Topology · Mathematics 2019-04-03 Ruth Charney , Matthew Cordes , Devin Murray

The Morse boundary of a proper geodesic metric space is designed to encode hypberbolic-like behavior in the space. A key property of this boundary is that a quasi-isometry between two such spaces induces a homeomorphism on their Morse…

Geometric Topology · Mathematics 2017-07-25 Ruth Charney , Devin Murray

We show that pseudo-Anosov mapping classes are generic in every Cayley graph of the mapping class group of a finite-type hyperbolic surface. Our method also yields an analogous result for rank-one CAT(0) groups and hierarchically hyperbolic…

Geometric Topology · Mathematics 2025-10-21 Inhyeok Choi

We prove that all hierarchically hyperbolic spaces have finite asymptotic dimension and obtain strong bounds on these dimensions. One application of this result is to obtain the sharpest known bound on the asymptotic dimension of the…

Group Theory · Mathematics 2017-05-04 Jason Behrstock , Mark F. Hagen , Alessandro Sisto

We prove that stability -- a strong quasiconvexity property -- pulls back under proper actions on proper metric spaces. This result has several applications, including that convex cocompact subgroups of both mapping class groups and outer…

Geometric Topology · Mathematics 2017-09-20 Tarik Aougab , Matthew Gentry Durham , Samuel J. Taylor

For a proper geodesic metric space $X$, the Morse boundary $\partial_*X$ focuses on the hyperbolic-like directions in the space $X$. It is a quasi-isometry invariant. That is, a quasi-isometry between two hyperbolic spaces induces a…

Geometric Topology · Mathematics 2020-04-24 Qing Liu

We provide an analysis of the dynamics of isometries and semicontractions of metric spaces. Certain subsets of the boundary at infinity play a fundamental role and are identified completely for the standard boundaries of CAT(0)-spaces,…

Metric Geometry · Mathematics 2014-11-11 Anders Karlsson

In 1995, Rips and Sela asked if torsionfree hyperbolic groups admit globally stable cylinders. We establish this property for all residually finite hyperbolic groups and curve graphs of finite-type surfaces. These cylinders are fine…

Geometric Topology · Mathematics 2025-01-24 Harry Petyt , Davide Spriano , Abdul Zalloum

We study the (Ahlfors regular) conformal dimension of the boundary at infinity of Gromov hyperbolic groups which split over elementary subgroups. If such a group is not virtually free, we show that the conformal dimension is equal to the…

Metric Geometry · Mathematics 2022-08-23 Matias Carrasco , John M. Mackay

We show that the sublinearly Morse boundary of a CAT(0) cubical group with a factor system is well-defined up to homeomorphism with respect to the visual topology. The key tool used in the proof is a new topology on sublinearly Morse…

Geometric Topology · Mathematics 2022-12-20 Carolyn Abbott , Merlin Incerti-Medici

F. Paulin proved that if the Gromov boundaries of two hyperbolic groups are quasi-Mobius equivalent, then the groups themselves are quasi-isometric. The goal of this article is to extend Paulin's result to the setting of relatively…

Geometric Topology · Mathematics 2026-02-25 Abhijit Pal , Rana Sardar

We consider cusped hyperbolic $n-$manifolds, and compute \v{C}ech cohomology groups of the Morse boundaries of their fundamental groups. In particular, we show that the reduced \v{C}ech cohomology with real coefficients vanishes in…

Group Theory · Mathematics 2026-03-25 Elia Fioravanti , Annette Karrer , Alessandro Sisto , Stefanie Zbinden

Many geometric structures associated to surface groups can be encoded in terms of invariant cross ratios on their circle at infinity; examples include points of Teichm\"uller space, Hitchin representations and geodesic currents. We add to…

Geometric Topology · Mathematics 2026-03-25 Jonas Beyrer , Elia Fioravanti

We show that a finite collection of stable subgroups of a finitely generated group has finite height, finite width and bounded packing. We then use knowledge about intersections of conjugates to characterize finite families of…

Geometric Topology · Mathematics 2017-02-06 Yago Antolín , Mahan Mj , Alessandro Sisto , Samuel J. Taylor

Let $\Gamma$ be a Gromov hyperbolic group, endowed with an arbitrary left-invariant hyperbolic metric, quasi-isometric to a word metric. The action of $\Gamma$ on its boundary $\partial\Gamma$ endowed with the Patterson-Sullivan measure…

Dynamical Systems · Mathematics 2016-08-24 Łukasz Garncarek