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Related papers: Hyperbolic quasi-geodesics in CAT(0) spaces

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We relate the topology of the Morse boundary of a group to geometric and algorithmic properties of the group. In particular, we show that a group has $\sigma$-compact Morse boundary if and only if it is Morse local-to-global. We also…

Group Theory · Mathematics 2026-05-13 Carolyn Abbott , Stefanie Zbinden

For any non-elementary hyperbolic group $\Gamma$, we find an outer automorphism invariant geodesic bicombing for the space of metric structures on $\Gamma$ equipped with a symmetrized version of the Thurston metric on Techim\"uller space.…

Geometric Topology · Mathematics 2025-03-31 Stephen Cantrell , Eduardo Reyes

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 if a proper metric space is quasi-isometric to a finitely generated group and to a space with a horoball over a finitely generated group, then that space is quasi-isometric to a rank-one symmetric space or the real line.

Group Theory · Mathematics 2026-04-16 Daniel Groves , Emily Stark , Genevieve S. Walsh , Kevin Whyte

We give an application of our earlier results concerning the quasiconformal extension of a germ of a conformal map to establish that in two dimensions the equipotential level lines of a capacitor are quasicircles whose distortion depends…

Complex Variables · Mathematics 2014-07-08 Gaven J. Martin

We describe a higher dimensional analogue of the Stallings folding sequence for group actions on CAT(0) cube complexes. We use it to give a characterization of quasiconvex subgroups of hyperbolic groups which act properly co-compactly on…

Group Theory · Mathematics 2017-09-01 Benjamin Beeker , Nir Lazarovich

We construct a one-to-one continuous map from the Morse boundary of a hierarchically hyperbolic group to its Martin boundary. This construction is based on deviation inequalities generalizing Ancona's work on hyperbolic groups. This…

Group Theory · Mathematics 2022-09-07 Matthew Cordes , Matthieu Dussaule , Ilya Gekhtman

We prove that every finite-volume hyperbolic 3-manifold M with p > 0 cusps admits a canonical, complete, piecewise Euclidean CAT(0) metric, with a canonical projection to a CAT(0) spine K. Moreover, (a) the universal cover of M endowed with…

Geometric Topology · Mathematics 2010-08-10 Iain R. Aitchison

The Morse local-to-global property generalizes the local-to-global property for quasi-geodesics in a hyperbolic space. We show that graph products of infinite Morse local-to-global groups have the Morse local-to-global property. To achieve…

Geometric Topology · Mathematics 2026-01-16 Joshua Perlmutter

We study the theory of convergence for CAT$(0)$-lattices (that is groups $\Gamma$ acting geometrically on proper, geodesically complete CAT$(0)$-spaces) and their quotients (CAT$(0)$-orbispaces). We describe some splitting and collapsing…

Metric Geometry · Mathematics 2024-05-06 Nicola Cavallucci , Andrea Sambusetti

Let $G$ be a finitely generated group. Cashen and Mackay proved that if the contracting boundary of $G$ with the topology of fellow travelling quasi-geodesics is compact then $G$ is a hyperbolic group. Let $\mathcal{H}$ be a finite…

Group Theory · Mathematics 2021-02-05 Abhijit Pal , Rahul Pandey

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

For each $g \ge 2$, we prove existence of a computable constant $\epsilon(g) > 0$ such that if $S$ is a strongly irreducible Heegaard surface of genus $g$ in a complete hyperbolic 3-manifold $M$ and $\gamma$ is a simple geodesic of length…

Geometric Topology · Mathematics 2014-10-01 William Breslin

We examine closed geodesics in the quotient of hyperbolic three space by the discrete group of isometries SL(2,Z[i]). There is a correspondence between closed geodesics in the manifold, the complex continued fractions originally studied by…

Number Theory · Mathematics 2019-07-09 Katie McKeon

We propose the metric notion of strong hyperbolicity as a way of obtaining hyperbolicity with sharp additional properties. Specifically, strongly hyperbolic spaces are Gromov hyperbolic spaces that are metrically well-behaved at infinity,…

Group Theory · Mathematics 2016-09-28 Bogdan Nica , Jan Spakula

We prove that, if a closed geodesic $\Gamma$ on a complete finite type hyperbolic surface has at least 2 self-intersections, then the length of $\Gamma$ has an lower bound $2\log(5+2\sqrt6)$, and the lower bound is sharp, attained on a…

Geometric Topology · Mathematics 2025-10-02 Wujie Shen

We prove the Borel Conjecture for a class of groups containing word-hyperbolic groups and groups acting properly, isometrically and cocompactly on a finite dimensional CAT(0)-space.

Geometric Topology · Mathematics 2010-03-26 Arthur Bartels , Wolfgang Lueck

We study different notions of quasiconvexity for a subgroup $H$ of a relatively hyperbolic group $G.$ The first result establishes equivalent conditions for $H$ to be relatively quasiconvex. As a corollary we obtain that the relative…

Group Theory · Mathematics 2011-10-12 Victor Gerasimov , Leonid Potyagailo

In the present paper we characterize the surjective isometries of the space of compact, convex subsets of proper, geodesically complete CAT(0)-spaces in which geodesics do not split, endowed with the Hausdorff metric. Moreover, an analogue…

Metric Geometry · Mathematics 2007-05-23 Thomas Foertsch

Let $\Gamma$ be a lattice in $\mathrm{SO}_0(n, 1)$. We prove that if the associated locally symmetric space contains infinitely many maximal totally geodesic subspaces of dimension at least $2$, then $\Gamma$ is arithmetic. This answers a…

Geometric Topology · Mathematics 2020-04-28 Uri Bader , David Fisher , Nick Miller , Matthew Stover