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Constant rescaling of a Riemannian metric appears in many computational settings, often through a global scale parameter that is introduced either explicitly or implicitly. Although this operation is elementary, its consequences are not…

Machine Learning · Computer Science 2026-01-29 Kisung You

Within a framework of noncommutative geometry, we develop an analogue of (pseudo) Riemannian geometry on finite and discrete sets. On a finite set, there is a counterpart of the continuum metric tensor with a simple geometric…

General Relativity and Quantum Cosmology · Physics 2009-10-31 A. Dimakis , F. Muller-Hoissen

We study isometric actions of Lie $2$-groups on Riemannian groupoids by exhibiting some of their immediate properties and implications. Firstly, we prove an existence result which allows both to obtain 2-equivariant versions of the Slice…

Differential Geometry · Mathematics 2023-07-19 Juan Sebastian Herrera-Carmona , Fabricio Valencia

In a family of compact, canonically polarized, complex manifolds the first variation of the lengths of closed geodesics is computed. As an application, we show the coincidence of the Fenchel-Nielsen and Weil-Petersson symplectic forms on…

Differential Geometry · Mathematics 2008-08-28 Reynir Axelsson , Georg Schumacher

This paper is the third in a series dedicated to the fundamentals of sub-Riemannian geometry and its implications in Lie groups theory: "Sub-Riemannian geometry and Lie groups. Part I", math.MG/0210189, available at…

Metric Geometry · Mathematics 2007-05-23 Marius Buliga

We describe how to approximate the Riemann curvature tensor as well as sectional curvatures on possibly infinite-dimensional shape spaces that can be thought of as Riemannian manifolds. To this end, we extend the variational time…

Numerical Analysis · Mathematics 2019-12-17 Alexander Effland , Behrend Heeren , Martin Rumpf , Benedikt Wirth

The famous Hopf-Rinow Theorem states, amongst others, that a Riemannian manifold is metrically complete if and only if it is geodesically complete. The Clifton-Pohl torus fails to be geodesically complete proving that this theorem cannot be…

Differential Geometry · Mathematics 2025-09-05 Annegret Burtscher

We define Wick-rotations by considering pseudo-Riemannian manifolds as real slices of a holomorphic Riemannian manifold. From a frame bundle viewpoint Wick-rotations between different pseudo-Riemannian spaces can then be studied through…

Differential Geometry · Mathematics 2018-03-14 Christer Helleland , Sigbjorn Hervik

We classify stacky curves in characteristic $p > 0$ with cyclic stabilizers of order $p$ using higher ramification data. This approach replaces the local root stack structure of a tame stacky curve, similar to the local structure of a…

Algebraic Geometry · Mathematics 2020-08-18 Andrew Kobin

This paper focuses on the study of open curves in a Riemannian manifold M, and proposes a reparametrization invariant metric on the space of such paths. We use the square root velocity function (SRVF) introduced by Srivastava et al. to…

Differential Geometry · Mathematics 2017-03-16 Alice Le Brigant

The comparison theory for the Riccati equation satisfied by the shape operator of parallel hypersurfaces is generalized to semi-Riemannian manifolds of arbitrary index, using one-sided bounds on the Riemann tensor which in the Riemannian…

dg-ga · Mathematics 2008-02-03 L. Andersson , R. Howard

This paper presents an overview of recent developments in the analysis of shapes such as curves and surfaces through Riemannian metrics. We show that several constructions of metrics on spaces of submanifolds can be unified through the…

Differential Geometry · Mathematics 2018-09-19 Martin Bauer , Nicolas Charon , Laurent Younes

The techniques and analysis presented in this paper provide new methods to solve optimization problems posed on Riemannian manifolds. A new point of view is offered for the solution of constrained optimization problems. Some classical…

Optimization and Control · Mathematics 2018-04-12 Steven Thomas Smith

The geometrical diffraction theory, in the sense of Keller,is here reconsidered as an obstacle problem in the Riemannian geometry. The first result is the proof of the existence and the analysis of the main properties of the diffracted…

Mathematical Physics · Physics 2007-05-23 Enrico De Micheli , Giacomo Monti Bragadin , Giovanni Alberto Viano

Geodesics escape is widely used to study the scattering of hyperbolic equations. However, there are few progresses except in a simply connected complete Riemannian manifold with nonpositive curvature. We propose a kind of complete…

Analysis of PDEs · Mathematics 2018-12-03 Zhen-Hu Ning , Fengyan Yang , Xiaopeng Zhao

In this paper we study geometries on the manifold of curves. We define a manifold $M$ where objects $c\in M$ are curves, which we parameterize as $c:S^1\to \real^n$ ($n\ge 2$, $S^1$ is the circle). Given a curve $c$, we define the tangent…

Differential Geometry · Mathematics 2007-05-23 A. Yezzi , A. Mennucci

In this paper geometry of Gromov-Hausdorff distance on the class of all metric spaces considered up to an isometry is investigated. For this class continuous curves and their lengths are defined, and it is shown that the Gromov-Hausdorff…

Metric Geometry · Mathematics 2020-09-02 S. I. Borzov , A. O. Ivanov , A. A. Tuzhilin

Sectional curvature bounds are of central importance in the study of Riemannian manifolds, both in smooth differential geometry and in the generalized synthetic setting of Alexandrov spaces. Riemannian metrics along with metric spaces of…

Differential Geometry · Mathematics 2026-01-30 Darius Erös , Michael Kunzinger , Argam Ohanyan , Alessio Vardabasso

The present paper shows that warped Riemannian metrics, a class of Riemannian metrics which play a prominent role in Riemannian geometry, are also of fundamental importance in information geometry. Precisely, the paper features a new…

Statistics Theory · Mathematics 2017-07-25 Salem Said , Lionel Bombrun , Yannick Berthoumieu

We propose a new Riemannian geometry for fixed-rank matrices that is specifically tailored to the low-rank matrix completion problem. Exploiting the degree of freedom of a quotient space, we tune the metric on our search space to the…

Machine Learning · Computer Science 2012-11-13 B. Mishra , K. Adithya Apuroop , R. Sepulchre