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Related papers: Generalised Baumslag-Solitar groups and Hierarchic…

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We introduce a new isomorphism invariant for generalized Baumslag-Solitar (GBS) groups, which we call the limit angle. Unlike previously known invariants, which are primarily algebraic, the limit angle admits a dynamical interpretation,…

Group Theory · Mathematics 2025-08-06 Dario Ascari , Montserrat Casals-Ruiz , Ilya Kazachkov

Given a finite graph of relatively hyperbolic groups with its fundamental group relatively hyperbolic and edge groups quasi-isometrically embedded and relatively quasiconvex in vertex groups, we prove that vertex groups are relatively…

Geometric Topology · Mathematics 2020-11-10 Abhijit Pal

Let $A$ be a finite dimensional $Q-$algebra and $\Gamma subset A$ a $Z-$order. We classify those $A$ with the property that $Z^2$ does not embed in $\mathcal{U}(\Gamma)$. We call this last property the hyperbolic property. We apply this in…

Rings and Algebras · Mathematics 2007-11-21 E. Iwaki , S. O. Juriaans , A. C. Souza Filho

We prove that the outer automorphism group of a one-ended hyperbolic group is virtually a hierarchically hyperbolic group (HHG), under mild orientability conditions on the associated JSJ decomposition. This is done by proving that a…

Group Theory · Mathematics 2026-05-25 Ervin Hadziosmanovic , Giorgio Mangioni

We show that infinite cyclic subgroups of groups acting uniformly properly on injective metric spaces are uniformly undistorted. In the special case of hierarchically hyperbolic groups, we use this to study translation lengths for actions…

Geometric Topology · Mathematics 2025-05-27 Carolyn Abbott , Mark Hagen , Harry Petyt , Abdul Zalloum

Given isometric actions by a group G on finitely many \delta-hyperbolic metric spaces, we provide a sufficient condition that guarantees the existence of a single element in G that is hyperbolic for each action. As an application we prove a…

Group Theory · Mathematics 2018-03-16 Matt Clay , Caglar Uyanik

We prove that the isomorphism problem is decidable for generalized Baumslag-Solitar (GBS) groups with one quasi-conjugacy class and full support gaps. In order to do so we introduce a family of invariants that fully characterize the…

Group Theory · Mathematics 2025-08-05 Dario Ascari , Montserrat Casals-Ruiz , Ilya Kazachkov

We demonstrate the quasi-isometry invariance of two important geometric structures for relatively hyperbolic groups: the coned space and the cusped space. As applications, we produce a JSJ-decomposition for relatively hyperbolic groups…

Group Theory · Mathematics 2013-08-22 Bradley Groff

The hyperbolic plane admits a quasi-isometric embedding into a hyperbolic group if and only if the group is not virtually free.

Group Theory · Mathematics 2007-05-23 Mario Bonk , Bruce Kleiner

We prove that quasi-isometries of horospherical products of hyperbolic spaces are geometrically rigid in the sense that they are uniformly close to product maps, this is a generalisation of the result obtained by Eskin, Fisher and Whyte in…

Differential Geometry · Mathematics 2026-04-08 Tom Ferragut

In this work, we are concerned with hierarchically hyperbolic spaces and hierarchically hyperbolic groups. Our main result is a wide generalization of a combination theorem of Behrstock, Hagen, and Sisto. In particular, as a consequence, we…

Group Theory · Mathematics 2019-09-25 Federico Berlai , Bruno Robbio

To an ergodic, essentially free and measure-preserving action of a non-amenable Baumslag-Solitar group on a standard probability space, a flow is associated. The isomorphism class of the flow is shown to be an invariant of such actions of…

Group Theory · Mathematics 2015-01-05 Yoshikata Kida

Suppose G is a hyperbolic group whose boundary has topological dimension k. If the boundary is quasisymmetrically homeomorphic to an Ahlfors k-regular metric space, then, modulo a finite normal subgroup, G is isomorphic to a uniform lattice…

Metric Geometry · Mathematics 2007-05-23 Mario Bonk , Bruce Kleiner

We propose a new model for random quotients of groups using independent random walks. In this model, we show that random quotients of acylindrical hyperbolic groups asymptotically almost surely remain acylindrically hyperbolic. Our main…

Group Theory · Mathematics 2026-01-28 Carolyn Abbott , Daniel Berlyne , Giorgio Mangioni , Thomas Ng , Alexander J. Rasmussen

We show that any group that is hyperbolic relative to virtually nilpotent subgroups, and does not admit peripheral splittings, contains a quasi-isometrically embedded copy of the hyperbolic plane. In natural situations, the specific…

Group Theory · Mathematics 2020-11-09 John M. Mackay , Alessandro Sisto

Using the projection complex machinery, Bestvina-Bromberg-Fujiwara, Hagen-Petyt and Han-Nguyen-Yang prove that several classes of nonpositively-curved groups admit equivariant quasi-isometric embeddings into finite products of quasi-trees,…

Group Theory · Mathematics 2026-05-06 Bingxue Tao

A symplectic form is called hyperbolic if its pull-back to the universal cover is a differential of a bounded one-form. The present paper is concerned with the properties and constructions of manifolds admitting hyperbolic symplectic forms.…

Symplectic Geometry · Mathematics 2007-11-27 Jarek Kedra

Actions on hyperbolic metric spaces are an important tool for studying groups, and so it is natural, but difficult, to attempt to classify all such actions of a fixed group. In this paper, we build strong connections between hyperbolic…

Group Theory · Mathematics 2022-07-27 Carolyn R. Abbott , Sahana Balasubramanya , Sam Payne , Alexander J. Rasmussen

We develop a notion of groups that act acylindrically and non-elementarily on simplicial trees, which we call acylindrically arboreal groups. We then prove a complete classification of when graph products of groups and the fundamental…

Group Theory · Mathematics 2026-01-16 William D. Cohen

Two groups have a common model geometry if they act properly and cocompactly by isometries on the same proper geodesic metric space. The Milnor-Schwarz lemma implies that groups with a common model geometry are quasi-isometric; however, the…

Geometric Topology · Mathematics 2021-05-17 Emily Stark , Daniel J. Woodhouse