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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

We derive an upper bound on the size of a ball such that the image of the ball under quadratic map is strongly convex and smooth. Our result is the best possible improvement of the analogous result by Polyak in the case of quadratic map. We…

Optimization and Control · Mathematics 2017-10-27 Anatoly Dymarsky

The notions of quasiconvexity, Wright convexity and convexity for functions defined on a metric Abelian group are introduced. Various characterizations of such functions, the structural properties of the functions classes so obtained are…

Classical Analysis and ODEs · Mathematics 2020-11-23 Włodzimierz Fechner , Zsolt Páles

In this paper it is proved that relative hyperbolicity is an invariant of quasi-isometry. As a byproduct of the arguments, simplified definitions of relative hyperbolicity are obtained. In particular we obtain a new definition very similar…

Group Theory · Mathematics 2007-05-23 Cornelia Drutu

We use analytic and numerical methods to obtain the solution of the Q-ball equation of motion. In particular, we show that the profile function of the three-dimensional Q-ball can be accurately approximated by the symmetrized Woods-Saxon…

High Energy Physics - Theory · Physics 2009-11-10 Theodora Ioannidou , N. D. Vlachos

A new intrinsic volume metric is introduced for the class of convex bodies in $\mathbb{R}^n$. As an application, an inequality is proved for the asymptotic best approximation of the Euclidean unit ball by arbitrarily positioned polytopes…

Metric Geometry · Mathematics 2023-03-15 Florian Besau , Steven Hoehner

The space of shapes of a polyhedron with given total angles less than 2\pi at each of its n vertices has a Kaehler metric, locally isometric to complex hyperbolic space CH^{n-3}. The metric is not complete: collisions between vertices take…

Geometric Topology · Mathematics 2007-05-23 William P. Thurston

The purpose of this paper is to study the notion of the quasihyperbolic volume and to find growth estimates for the quasihyperbolic volume of balls in a domain $G \subset {\mathbb R}^n\,$ in terms of the radii.

Metric Geometry · Mathematics 2017-07-27 Xiaohui Zhang , Riku Klén , Ville Suomala , Matti Vuorinen

In this note, we present examples of non-quasi-geodesic metric spaces which are hyperbolic (i.e., satisfying the Gromov's $4$-point condition) while the intersection of any two metric balls therein does not either "look like" a ball or has…

Metric Geometry · Mathematics 2024-11-20 Qizheng You , Jiawen Zhang

By virtue of a weak comparison principle in small domains we prove axial symmetry in convex and symmetric smooth bounded domains as well as radial symmetry in balls for regular solutions of a class of quasi-linear elliptic systems in…

Analysis of PDEs · Mathematics 2009-07-02 Luigi Montoro , Berardino Sciunzi , Marco Squassina

We mainly consider two metrics: a Gromov hyperbolic metric and a scale invariant Cassinian metric. We compare these two metrics and obtain their relationship with certain well-known hyperbolic-type metrics, leading to several inclusion…

Metric Geometry · Mathematics 2017-05-25 Manas Ranjan Mohapatra , Swadesh Kumar Sahoo

We survey some basic geometric properties of the Funk metric of a convex set in $\mathbb{R}^n$. In particular, we study its geodesics, its topology, its metric balls, its convexity properties, its perpendicularity theory and its isometries.…

Metric Geometry · Mathematics 2014-06-27 Athanase Papadopoulos , Marc Troyanov

Let $(M, \partial M)$ be a compact 3-manifold with boundary which admits a complete, convex co-compact hyperbolic metric. For each hyperbolic metric $g$ on $M$ such that $\dr M$ is smooth and strictly convex, the induced metric on $\dr M$…

Geometric Topology · Mathematics 2007-05-23 Jean-Marc Schlenker

Volume of metric balls relates to rate-distortion theory and packing bounds on codes. In this paper, the volume of balls in complex Grassmann manifolds is evaluated for an arbitrary radius. The ball is defined as a set of hyperplanes of a…

Information Theory · Computer Science 2015-08-04 Renaud-Alexandre Pitaval , Lu Wei , Olav Tirkkonen , Jukka Corander

In this paper we study the area of ideals triangles in a convex domain with its Hilbert geometry. We obtain a characterization of the hyperbolic geometry among all the Hilbert geometry in terms of area of ideals triangles. We also obtain a…

Differential Geometry · Mathematics 2009-09-29 Bruno Colbois , Constantin Vernicos , Patrick Verovic

In this paper, we introduce a notion of the center and radius of a subset A of metric space X. In the Euclidean spaces, this notion can be seen as the extension of the center and radius of open/closed balls. The center and radius of a…

General Topology · Mathematics 2024-08-22 Akhilesh Badra , Hemant Kumar Singh

We study properties of "hyperbolic directions" in groups acting cocompactly on properly convex domains in real projective space, from three different perspectives simultaneously: the (coarse) metric geometry of the Hilbert metric, the…

Geometric Topology · Mathematics 2025-07-22 Mitul Islam , Theodore Weisman

In this paper some concepts of convex analysis on hyperbolic space are studied. We first study properties of the intrinsic distance, for instance, we present the spectral decomposition of its Hessian. Next, we study the concept of convex…

Optimization and Control · Mathematics 2022-07-13 Orizon Pereira Ferreira , Sándor Zoltán Németh , Jinzhen Zhu

Complete hyperbolicity of small Euclidean balls with respect to a C^1-smooth almost complex structure standard at origin is improved to give a complete hyperbolicity of strictly pseudoconvex domains. More precise (and lower) regularity…

Complex Variables · Mathematics 2007-05-23 S. Ivashkovich , J. -P. Rosay

In this paper we study the class of so called `ball-bodies' in ${\mathbb R}^n$, given by intersections of translates of Euclidean unit balls (or, equivalently, summand of the Euclidean ball). We study the class along with the natural…

Metric Geometry · Mathematics 2025-05-20 Shiri Artstein-Avidan , Dan I. Florentin