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We introduce diffusion geometry as a new framework for geometric and topological data analysis. Diffusion geometry uses the Bakry-Emery $\Gamma$-calculus of Markov diffusion operators to define objects from Riemannian geometry on a wide…

Metric Geometry · Mathematics 2024-07-03 Iolo Jones

We compute the gap distribution of directions of saddle connections for two classes of translation surfaces. One class will be the translation surfaces arising from gluing two identical tori along a slit. These yield the first explicit…

Dynamical Systems · Mathematics 2020-06-30 Anthony Sanchez

Let $G$ be a group such that $G/Z(G)$ is finite and simple. The non-commuting, non-generating graph $\Xi(G)$ of $G$ has vertex set $G \setminus Z(G)$, with edges corresponding to pairs of elements that do not commute and do not generate…

Group Theory · Mathematics 2026-02-20 Saul D. Freedman

Let the metric space $\mathbb R^n \setminus \sim$ be the metric space of $n$-sized unordered tuples of real numbers. In the following, it will be shown that if a function $\varphi: \mathbb R^m \to \mathbb R^n \setminus \sim$ is continuous,…

Metric Geometry · Mathematics 2014-06-24 Adrian Fellhauer

Increasing evidence shows that warped disks are common, challenging the methods used to model their velocity fields. Molecular line emission of these disks is characterized by a twisted pattern, similar to the signal from radial flows,…

Earth and Planetary Astrophysics · Physics 2024-12-04 A. Zuleta , T. Birnstiel , R. Teague

In this article, we show that the algorithm of maintaining expander decompositions in graphs undergoing edge deletions directly by removing sparse cuts repeatedly can be made efficient. Formally, for an $m$-edge undirected graph $G$, we say…

Data Structures and Algorithms · Computer Science 2023-01-24 Yiding Hua , Rasmus Kyng , Maximilian Probst Gutenberg , Zihang Wu

We measure the pitch angle ($\varphi$) of spiral arms in a sample of 79 galaxies to perform a systematic study of the dependence of $\varphi$ on galaxy morphology, mass, and kinematics to investigate the physical origin of spiral arms. We…

Astrophysics of Galaxies · Physics 2022-09-12 Si-Yue Yu , Luis C. Ho

We show that $\{0,\varphi+3,-3\varphi+2,-\varphi+\frac{5}{2}\}$ is the set of slopes of nonexpansive directions for a minimal subshift in the Jeandel-Rao Wang shift, where $\varphi=(1+\sqrt{5})/2$ is the golden mean. This set is a…

Dynamical Systems · Mathematics 2023-10-09 Sébastien Labbé , Casey Mann , Jennifer McLoud-Mann

We consider a two-phase heat conductor in $\mathbb R^N$ with $N \geq 2$ consisting of a core and a shell with different constant conductivities. We study the role played by radial symmetry for overdetermined problems of elliptic and…

Analysis of PDEs · Mathematics 2020-04-14 Lorenzo Cavallina , Rolando Magnanini , Shigeru Sakaguchi

The radius and diameter are fundamental graph parameters. They are defined as the minimum and maximum of the eccentricities in a graph, respectively, where the eccentricity of a vertex is the largest distance from the vertex to another…

Data Structures and Algorithms · Computer Science 2015-06-08 Amir Abboud , Virginia Vassilevska Williams , Joshua Wang

A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the gain function $ \varphi $ assigns a unit complex number to each orientation of an edge of $ G $ and its inverse is assigned to the opposite…

Combinatorics · Mathematics 2023-12-29 Aniruddha Samanta , M. Rajesh Kannan

Geometric moment invariants (GMIs) have been widely used as basic tool in shape analysis and information retrieval. Their structure and characteristics determine efficiency and effectiveness. Two fundamental building blocks or generating…

Computer Vision and Pattern Recognition · Computer Science 2017-05-26 Erbo Li , Yazhou Huang , Dong Xu , Hua Li

In the light of $\phi$-mapping method and topological current theory, the topological structure and the topological quantization of arbitrary dimensional topological defects are obtained under the condition that the Jacobian $J(\phi/v) \neq…

High Energy Physics - Theory · Physics 2007-05-23 Yishi Duan , Ying Jiang , Guohong Yang

We study noncommutative Ricci flow in a finite dimensional representation of a noncommutative torus. It is shown that the flow exists and converges to the flat metric. We also consider the evolution of entropy and a definition of scalar…

Mathematical Physics · Physics 2014-02-10 Rocco Duvenhage

This paper studies the convexity properties of nonsmooth extended-real-valued weakly convex functions, a class of functions that is central to modern optimization and its applications. We establish new characterizations of convexity using…

Optimization and Control · Mathematics 2026-03-27 Vo Thanh Phat

We extend results of parametric geometry of numbers to a general diagonal flow on the space of lattices. Moreover, we compute the Hausdorff dimension of the set of trajectories with every given behavior, with respect to a nonstandard metric…

Dynamical Systems · Mathematics 2021-07-27 Omri Nisan Solan

Bridging geometry and topology, curvature is a powerful and expressive invariant. While the utility of curvature has been theoretically and empirically confirmed in the context of manifolds and graphs, its generalization to the emerging…

Machine Learning · Computer Science 2023-04-07 Corinna Coupette , Sebastian Dalleiger , Bastian Rieck

We study the problem of approximating all-pair distances in a weighted undirected graph with differential privacy, introduced by Sealfon [Sea16]. Given a publicly known undirected graph, we treat the weights of edges as sensitive…

Data Structures and Algorithms · Computer Science 2025-04-07 Michael Dinitz , Chenglin Fan , Jingcheng Liu , Jalaj Upadhyay , Zongrui Zou

We introduce a novel, geometry-aware distance metric for the family of von Mises-Fisher (vMF) distributions, which are fundamental models for directional data on the unit hypersphere. Although the vMF distribution is widely employed in a…

Machine Learning · Statistics 2025-04-22 Kisung You , Dennis Shung , Mauro Giuffrè

We review the mechanism in quantum gravity whereby topological geons, particles made from non-trivial spatial topology, are endowed with nontrivial spin and statistics. In a theory without topology change there is no obstruction to…

General Relativity and Quantum Cosmology · Physics 2014-11-17 H. F. Dowker , R. D. Sorkin