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Tree-graded spaces are a generalization of $\mathbb{R}$-trees and play an important role in describing the large-scale geometry of relatively hyperbolic groups. We consider a subclass of tree-graded spaces that we call "disjointly…

Algebraic Topology · Mathematics 2026-03-10 Jeremy Brazas , Curtis Kent

We describe those complete linearly ordered topological spaces $X$ which are homogeneous (=CHLOTS). That is, $X$ is order isomorphic with any nonempty open interval in $X$. Using countable tail-like ordinals as indices, we build towers of…

General Topology · Mathematics 2021-09-22 Ethan Akin , Karel Hrbacek

Learning the representation of data with hierarchical structures in the hyperbolic space attracts increasing attention in recent years. Due to the constant negative curvature, the hyperbolic space resembles tree metrics and captures the…

Machine Learning · Computer Science 2022-02-21 Huiru Xiao , Caigao Jiang , Yangqiu Song , James Zhang , Junwu Xiong

We study the random planar maps obtained from supercritical Galton--Watson trees by adding the horizontal connections between successive vertices at each level. These are the hyperbolic analog of the maps studied by Curien, Hutchcroft and…

Probability · Mathematics 2019-09-30 Thomas Budzinski

Many high-dimensional practical data sets have hierarchical structures induced by graphs or time series. Such data sets are hard to process in Euclidean spaces and one often seeks low-dimensional embeddings in other space forms to perform…

Machine Learning · Computer Science 2022-04-13 Chao Pan , Eli Chien , Puoya Tabaghi , Jianhao Peng , Olgica Milenkovic

In this paper we investigate the geometric properties of quasi-trees, and prove some equivalent criteria. We give a general construction of a tree that approximates the ends of a geodesic space, and use this to prove that every quasi-tree…

Metric Geometry · Mathematics 2023-08-28 Alice Kerr

We investigate CAT(0) metric spaces whose associated Tits boundary is compact. Prominent examples of such spaces are of course the euclidean ones. However there exist non trivial geodesically complete CAT(0) spaces with compact Tits…

Metric Geometry · Mathematics 2011-06-06 Aurélien Bosché

We prove a general criterion for a metric space to have conformal dimension one. The conditions are stated in terms of the existence of enough local cut points in the space. We then apply this criterion to the boundaries of hyperbolic…

Metric Geometry · Mathematics 2013-11-05 Matias Carrasco Piaggio

Embedded topic models are able to learn interpretable topics even with large and heavy-tailed vocabularies. However, they generally hold the Euclidean embedding space assumption, leading to a basic limitation in capturing hierarchical…

Information Retrieval · Computer Science 2022-10-20 Yishi Xu , Dongsheng Wang , Bo Chen , Ruiying Lu , Zhibin Duan , Mingyuan Zhou

Hyperbolic-spaces are better suited to represent data with underlying hierarchical relationships, e.g., tree-like data. However, it is often necessary to incorporate, through alignment, different but related representations meaningfully.…

Machine Learning · Statistics 2020-12-03 Andrés Hoyos-Idrobo

We study the unitary boundary representation of a strongly transitive group acting on a right-angled hyperbolic building. We show its irreducibility. We do so by associating to such a representation a representation of a certain Hecke…

Dynamical Systems · Mathematics 2015-06-23 Uri Bader , Jan Dymara

It is known that PQ-symmetric maps on the boundary characterize the quasi-isometry type of visual hyperbolic spaces, in particular, of geodesically complete \br-trees. We define a map on pairs of PQ-symmetric ultrametric spaces which…

Geometric Topology · Mathematics 2010-02-08 Álvaro Martínez-Pérez

In this paper, we study the capacity dimension of the boundary of $CAT(0)$ spaces. We first compare the two metrics on the boundary of a hyperbolic $CAT(0)$ space, i.e., the visual metric and the conical metric, and prove that they give the…

Geometric Topology · Mathematics 2019-09-25 Dawei Wang

We already saw in [A1] that the space of dynamically marked rational maps can be identified to a subspace of the space of covers between trees of spheres on which there is a notion of convergence that makes it sequentially compact. In the…

Dynamical Systems · Mathematics 2017-09-15 Matthieu Arfeux

The theory of geometric structures on a surface with nonempty boundary can be developed by using a decomposition of such a surface into hexagons, in the same way as the theory of geometric structures on a surface without boundary is…

Geometric Topology · Mathematics 2012-10-02 Athanase Papadopoulos , Guillaume Théret

We develop a notion of rank one properly convex domains (or Hilbert geometries) in the real projective space. This is in the spirit of rank one non-positively curved Riemannian manifolds and CAT(0) spaces. We define rank one isometries for…

Geometric Topology · Mathematics 2025-06-11 Mitul Islam

We classify, up to orbit equivalence, all cohomogeneity one actions on the hyperbolic planes over the complex, quaternionic and Cayley numbers, and on the complex hyperbolic spaces of dimension greater than two. For the quaternionic…

Differential Geometry · Mathematics 2007-05-23 Jurgen Berndt , Hiroshi Tamaru

We define metrics in space that are natural counterparts of the hyperbolic metric in plane domains, using the characterization of the hyperbolic metric due to Beardon and Pommerenke. We obtain inequalities for these metrics under…

Complex Variables · Mathematics 2026-05-27 Aimo Hinkkanen , Poranee Khayo

Given any elliptic system with $t$-independent coefficients in the upper-half space, we obtain representation and trace for the conormal gradient of solutions in the natural classes for the boundary value problems of Dirichlet and Neumann…

Classical Analysis and ODEs · Mathematics 2015-11-06 Pascal Auscher , Mihalis Mourgoglou

Suppose that N is a geometrically finite orientable hyperbolic 3-manifold. Let P(N,C) be the space of all geometrically finite hyperbolic structures on N whose convex core is bent along a set C of simple closed curves. We prove that the map…

Geometric Topology · Mathematics 2007-05-23 Young-Eun Choi , Caroline Series