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Since optimization on Riemannian manifolds relies on the chosen metric, it is appealing to know that how the performance of a Riemannian optimization method varies with different metrics and how to exquisitely construct a metric such that a…

Optimization and Control · Mathematics 2025-02-19 Bin Gao , Renfeng Peng , Ya-xiang Yuan

We derive general structure and rigidity theorems for submetries $f: M \to X$, where $M$ is a Riemannian manifold with sectional curvature $\sec M \ge 1$. When applied to a non-trivial Riemannian submersion, it follows that $diam X \leq…

Differential Geometry · Mathematics 2014-04-16 Xiaoyang Chen , Karsten Grove

In recent years, manifold learning has become increasingly popular as a tool for performing non-linear dimensionality reduction. This has led to the development of numerous algorithms of varying degrees of complexity that aim to recover man…

Machine Learning · Statistics 2013-06-03 Dominique Perraul-Joncas , Marina Meila

We apply Cartan's method of equivalence to construct invariants of a given null hypersurface in a Lorentzian space-time. This enables us to fully classify the internal geometry of such surfaces and hence solve the local equivalence problem…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Paweł Nurowski , David C. Robinson

This article is the introductory part of authors PhD thesis. The article presents a new coordinate invariant definition of quasiregular and quasiconformal mappings on Riemannian manifolds that generalizes the definition of quasiregular…

Differential Geometry · Mathematics 2014-08-12 Tony Liimatainen

For a closed Riemannian manifold $M$ with a compact Lie group $G$ acting by isometries, we show that there are infinitely many $G$-invariant minimal hypersurfaces. Under the assumption that $M$ contains at most a finite number of minimal…

Differential Geometry · Mathematics 2026-04-16 Xingzhe Li , Tongrui Wang

We study a normalized version of the second order renormalization group flow on closed Riemannian surfaces. We discuss some general properties of this flow and establish several basic formulas. In particular, we focus on surfaces with zero…

Differential Geometry · Mathematics 2017-01-25 Volker Branding

The present paper is devoted to questions located at the junction of the theory of space quasiconformal mappings and Riemannian surfaces. Theorems on local behavior of one class of open discrete mappings with unbounded characteristic of…

Complex Variables · Mathematics 2015-02-19 D. P. Ilyutko , E. A. Sevost'yanov

These notes give an informal and leisurely introduction to $\mathrm{G}_2$ geometry for beginners. A special emphasis is placed on understanding the special linear algebraic structure in $7$ dimensions that is the pointwise model for…

Differential Geometry · Mathematics 2020-06-09 Spiro Karigiannis

In this paper, we consider surfaces in 4--dimensional pseudo--Riemannian space--forms with index 2. First, we obtain some of geometrical properties of such surfaces considering their relative null space. Then, we get classifications of…

Differential Geometry · Mathematics 2019-10-30 Burcu Bektaş Demirci , Nurettin Cenk Turgay

We use a construction which we call generalized cylinders to give a new proof of the fundamental theorem of hypersurface theory. It has the advantage of being very simple and the result directly extends to semi-Riemannian manifolds and to…

Differential Geometry · Mathematics 2019-01-08 Christian Baer , Paul Gauduchon , Andrei Moroianu

The logarithmic Riemann surface Sigma_{log} is a classical holomorphic 1-manifold. It lives into R^4 and induces a covering space of C - 0 defined by exp. This paper suggests a geometric construction of it, derived as the limit of a…

Differential Geometry · Mathematics 2007-05-23 Nikolaos I. Katzourakis

A few formulas and theorems for statistical structures are proved. They deal with various curvatures as well as with metric properties of the cubic form or its covariant derivative. Some of them generalize formulas and theorems known in the…

Differential Geometry · Mathematics 2021-05-12 Barbara Opozda

We investigate the geometric and topological structure of equidistant decompositions of Riemannian manifolds.

Differential Geometry · Mathematics 2022-12-21 Vitali Kapovitch , Alexander Lytchak

For a complete noncompact connected Riemannian manifold with bounded geometry, we prove the existence of isoperimetric regions in a larger space obtained by adding finitely many limit manifolds at infinity. As one of many possible…

Differential Geometry · Mathematics 2015-10-30 Stefano Nardulli

We obtain improved local well-posedness results for the Lorentzian timelike minimal surface equation. In dimension $d=3$, for a surface of arbitrary co-dimension, we show a gain of $1/3$ derivative regularity compared to a generic equation…

Analysis of PDEs · Mathematics 2025-04-03 Georgios Moschidis , Igor Rodnianski

The localization technique from convex geometry is generalized to the setting of Riemannian manifolds whose Ricci curvature is bounded from below. In a nutshell, our method is based on the following observation: When the Ricci curvature is…

Differential Geometry · Mathematics 2014-08-28 Bo'az Klartag

In this paper, we study Riemannian zeroth-order optimization in settings where the underlying Riemannian metric $g$ is geodesically incomplete, and the goal is to approximate stationary points with respect to this incomplete metric. To…

Machine Learning · Computer Science 2026-04-14 Shaocong Ma , Heng Huang

We study the space of all tilings which can be obtained using the Robinson tiles (this is a two-dimensional subshift of finite type). We prove that it has a unique minimal subshift, and describe it by means of a substitution. This…

Dynamical Systems · Mathematics 2012-03-08 Franz Gähler , Antoine Julien , Jean Savinien

This paper explores the null space properties of neural networks. We extend the null space definition from linear to nonlinear maps and discuss the presence of a null space in neural networks. The null space of a given neural network can…

Computer Vision and Pattern Recognition · Computer Science 2024-01-22 Xiang Li , Kevin M. Short
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