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Metric magnitude is a measure of the "size" of point clouds with many desirable geometric properties. It has been adapted to various mathematical contexts and recent work suggests that it can enhance machine learning and optimization…

Machine Learning · Computer Science 2024-09-09 Rayna Andreeva , James Ward , Primoz Skraba , Jie Gao , Rik Sarkar

We study quasi-modular pseudometric spaces as asymmetric refinements of modular metric structures. To each such space we associate canonical forward and backward quasi-uniformities and the corresponding directional topologies. We introduce…

General Topology · Mathematics 2026-02-03 Philani Rodney Majozi

This survey contains a selection of topics unified by the concept of positive semi-definiteness (of matrices or kernels), reflecting natural constraints imposed on discrete data (graphs or networks) or continuous objects (probability or…

Classical Analysis and ODEs · Mathematics 2019-11-13 Alexander Belton , Dominique Guillot , Apoorva Khare , Mihai Putinar

The paper is devoted to a categorical study of the category of probabilistic metric spaces. The study is based on an isomorphic description of the category of probabilistic metric spaces. The isomorphic description was obtained in [3] and…

General Topology · Mathematics 2026-04-02 Eva Colebunders , Robert Lowen

Diversities have been recently introduced as a generalization of metrics for which a rich tight span theory could be stated. In this work we take up a number of questions about hyperconvexity, diversities and fixed points of nonexpansive…

Metric Geometry · Mathematics 2016-10-05 Bozena Piatek , Rafa Espinola

We characterize the finite dimensional asymmetric normed spaces which are right bounded and the relation of this property with the natural compactness properties of the unit ball, as compactness and strong compactness. In contrast with some…

General Topology · Mathematics 2017-02-15 Natalia Jonard-Pérez , Enrique A. Sánchez-Pérez

M. Gromov introduced the mean dimension for a continuous map in the late 1990's, which is an invariant under topological conjugacy. On the other hand, the notion of metric mean dimension for a dynamical system was introduced by…

Dynamical Systems · Mathematics 2021-10-12 Jeovanny de Jesus Muentes Acevedo

The Leinster matrix corresponding to a finite category has entries counting the number of morphisms between objects. A first question is to know which positive integer matrices come from at least one finite category. Here, that question…

Category Theory · Mathematics 2008-12-18 Samer Allouch

A test space is the set of outcome-sets associated with a collection of experiments. This notion provides a simple mathematical framework for the study of probabilistic theories -- notably, quantum mechanics -- in which one is faced with…

Quantum Physics · Physics 2009-11-10 Alexander Wilce

A compact set has computable type if any homeomorphic copy of the set which is semicomputable is actually computable. Miller proved that finite-dimensional spheres have computable type, Iljazovi\'c and other authors established the property…

Logic · Mathematics 2023-07-10 Djamel Eddine Amir , Mathieu Hoyrup

Let $(X,d)$ be an unbounded metric space and $\tilde r=(r_n)_{n\in\mathbb N}$ be a scaling sequence of positive real numbers tending to infinity. We define the pretangent space $\Omega_{\infty, \tilde r}^{X}$ to $(X, d)$ at infinity as a…

Metric Geometry · Mathematics 2017-08-18 Viktoriia Bilet , Oleksiy Dovgoshey

This paper considers the existence of conformally compact Einstein metrics on 4-manifolds. A reasonably complete understanding is obtained for the existence of such metrics with prescribed conformal infinity, when the conformal infinity is…

Differential Geometry · Mathematics 2008-03-18 Michael T. Anderson

We begin to study classical dimension theory from the computable analysis (TTE) point of view. For computable metric spaces, several effectivisations of zero-dimensionality are shown to be equivalent. The part of this characterisation that…

Logic · Mathematics 2015-07-01 Robert Kenny

A strong submeasure on a compact metric space X is a sub-linear and bounded operator on the space of continuous functions on X. A strong submeasure is positive if it is non-decreasing. By Hahn-Banach theorem, a positive strong submeasure is…

Dynamical Systems · Mathematics 2019-10-16 Tuyen Trung Truong

We obtain a compactness result for various classes of Riemannian metrics in dimension four; in particular our method applies to anti-self-dual metrics, Kahler metrics with constant scalar curvature, and metrics with harmonic curvature. With…

Differential Geometry · Mathematics 2009-08-26 Jeff Viaclovsky , Gang Tian

The main result of this paper is that the space of conformally compact Einstein metrics on a given manifold is a smooth, infinite dimensional Banach manifold, provided it is non-empty, generalizing earlier work of Graham-Lee and Biquard. We…

Differential Geometry · Mathematics 2010-03-16 Michael T. Anderson

Diversities are a generalization of metric spaces, where instead of the non-negative function being defined on pairs of points, it is defined on arbitrary finite sets of points. Diversities have a well-developed theory. This includes the…

Metric Geometry · Mathematics 2020-10-23 David Bryant , Raúl Felipe , Mauricio Toledo-Acosta , Paul Tupper

Symmetric Positive Definite (SPD) matrices have been widely used in medical data analysis and a number of different Riemannian met-rics were proposed to compute with them. However, there are very few methodological principles guiding the…

Differential Geometry · Mathematics 2019-06-05 Yann Thanwerdas , Xavier Pennec

Connectedness, path connectedness, and uniform connectedness are well-known concepts. In the traditional presentation of these concepts there is a substantial difference between connectedness and the other two notions, namely connectedness…

General Topology · Mathematics 2015-11-06 Ittay Weiss

Quantitative algebras are $\Sigma$-algebras acting on metric spaces, where operations are nonexpanding. Mardare, Panangaden and Plotkin introduced 1-basic varieties as categories of quantitative algebras presented by quantitative equations.…

Category Theory · Mathematics 2026-02-06 J. Adámek , M. Dostál , J. Velebil