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Related papers: Some remarks on the visual angle metric

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We provide sharp estimates for the intrinsic distances of Finsler metrics with precise boundary estimates. These metrics include the Kobayashi-Hilbert metric near strongly convex points, the minimal metric near convex and strongly minimally…

Differential Geometry · Mathematics 2026-02-17 Matteo Fiacchi , Nikolai Nikolov

We will consider close-to-convexity of the metric balls defined by the quasihyperbolic metric and the $j$-metric. We will show that the $j$-metric balls with small radii are close-to-convex in general subdomains of $\Rn$ and the…

Metric Geometry · Mathematics 2010-10-08 Riku Klén

The Hilbert metric on convex subsets of $\mathbb R^n$ has proven a rich notion and has been extensively studied. We propose here a generalization of this metric to subset of complex projective spaces and give examples of applications to…

Metric Geometry · Mathematics 2022-03-25 Elisha Falbel , Antonin Guilloux , Pierre Will

We prove a functional identity between the Hilbert metric and the visual angle metric in the unit disk. The proof utilizes the Poincar\'e hyperbolic metric in terms of which both metrics can be expressed. This identity then yields sharp…

Complex Variables · Mathematics 2025-02-26 Sahsene Altinkaya , Masayo Fujimura , Matti Vuorinen

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

Although the hyperbolic metric possesses many remarkable properties, it is not defined on arbitrary subdomains of $\mathbb{R}^n$ with $n \geq 2$. This article introduces a new hyperbolic-type metric that provides an alternative approach to…

Metric Geometry · Mathematics 2025-08-01 Bibekananda Maji , Pritam Naskar , Swadesh Kumar Sahoo

We prove that a symmetric nonnegative function of two variables on a Lebesgue space that satisfies the triangle inequality for almost all triples of points is equivalent to some semimetric. Some other properties of metric triples (spaces…

Metric Geometry · Mathematics 2011-12-13 F. V. Petrov , P. B. Zatitskiy

The distortion of six different intrinsic metrics and quasi-metrics under conformal and quasiregular mappings is studied in a few simple domains $G\subsetneq\mathbb{R}^n$. The already known inequalities between the hyperbolic metric and…

Metric Geometry · Mathematics 2023-03-16 Oona Rainio

Let $K$ be a square in the plane and $\rho_K(x,y)$ be the hyperbolic distance between $x$, $y\in K$. Denote by $s_K(x,y)$ the triangular ratio metric in $K$; for $x\neq y$ the value of $s_K(x,y)$ equals the ratio of the Euclidean distance…

Complex Variables · Mathematics 2026-05-26 A. Kushaeva , S. Nasyrov

On any proper convex domain in real projective space there exists a natural Riemannian metric, the Blaschke metric. On the other hand, distances between points can be measured in the Hilbert metric. Using techniques of optimal control, we…

Differential Geometry · Mathematics 2021-02-23 Roland Hildebrand

We investigate several topics of triangle geometry in the elliptic and in the extended hyperbolic plane, such as: centers based on orthogonality, centers related to circumcircles and incircles, radical centers and centers of similitude,…

Metric Geometry · Mathematics 2019-08-30 Manfred Evers

The M\"obius metric $\delta_G$ is studied in the cases where its domain $G$ is an open sector of the complex plane. We introduce upper and lower bounds for this metric in terms of the hyperbolic metric and the angle of the sector, and then…

Metric Geometry · Mathematics 2023-03-16 Oona Rainio , Matti Vuorinen

This article shows how to express relativistic concepts in a visual manner using the full power of hyperbolic trigonometric functions. Minkowski diagrams in energy-momentum space are used in conjunction with hyperbolic triangles. Elegant…

General Relativity and Quantum Cosmology · Physics 2026-03-26 Karol Urbański

This paper deals with local convexity properties of the quasihyperbolic metric in the punctured space. We consider convexity and starlikeness of quasihyperbolic balls.

Metric Geometry · Mathematics 2009-10-14 Riku Klen

Given a domain $G \subsetneq \Rn$ we study the quasihyperbolic and the distance ratio metrics of $G$ and their connection to the corresponding metrics of a subdomain $D \subset G$. In each case, distances in the subdomain are always larger…

Metric Geometry · Mathematics 2013-11-19 Riku Klén , Yaxiang Li , Matti Vuorinen

This notes explores angle structures on ideally triangulated compact $3$-manifolds with high genus boundary. We show that the existence of angle structures implies the existence of a hyperbolic metric with totally geodesic boundary, and…

Geometric Topology · Mathematics 2014-05-13 Faze Zhang , Ruifeng Qiu , Tian Yang

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

Three hyperbolic type metrics including the triangular ratio metric, the $j^*$-metric and the M\"obius metric are studied in an annular ring. The Euclidean midpoint rotation is introduced as a method to create upper and lower bounds for…

Metric Geometry · Mathematics 2023-03-16 Oona Rainio

An improved version of quasiinvariance property of the quasihyperbolic metric under M\"obius transformations of the unit ball in ${\mathbb R}^n, n \ge 2,$ is given. Next, a quasiinvariance property, sharp in a local sense, of the…

Complex Variables · Mathematics 2013-11-19 Riku Klén , Matti Vuorinen , Xiaohui Zhang

We establish geometric relationships between the average scale-invariant Cassinian metric and other hyperbolic type metrics. In addition, we study the local convexity properties of the scale-invariant metric balls in Euclidean once…

Metric Geometry · Mathematics 2025-07-29 Manas Mohapatra , Antti Rasila , Matti Vuorinen