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A geometric flow based in the Riemann-Christoffel curvature tensor that in two dimensions has some common features with the usual Ricci flow is presented. For $n$ dimensional spaces this new flow takes into account all the components of the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Patricio S. Letelier

This paper is a review on recently found connection between geodesically equivalent metrics and integrable geodesic flows. Suppose two different metrics on one manifold have the same geodesics. We show that then the geodesic flows of these…

Differential Geometry · Mathematics 2011-08-08 Vladimir S. Matveev , Petar J. Topalov

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

In the shape analysis approach to computer vision problems, one treats shapes as points in an infinite-dimensional Riemannian manifold, thereby facilitating algorithms for statistical calculations such as geodesic distance between shapes…

Differential Geometry · Mathematics 2018-03-30 Sebastian Kurtek , Tom Needham

We define a formal Riemannian metric on a given conformal class of metrics on a closed Riemann surface. We show interesting formal properties for this metric, in particular the curvature is nonpositive and the Liouville energy is…

Differential Geometry · Mathematics 2015-07-20 Matthew J. Gursky , Jeffrey Streets

In this paper, it is elaborated the theory the Ricci flows for manifolds enabled with nonintegrable (nonholonomic) distributions defining nonlinear connection structures. Such manifolds provide a unified geometric arena for nonholonomic…

Differential Geometry · Mathematics 2007-05-23 Sergiu I. Vacaru

In this paper, on 4-spheres equipped with Riemannian metrics we study some integral conformal invariants, the sign and size of which under Ricci flow characterize the standard 4-sphere. We obtain a conformal gap theorem, and for Yamabe…

Differential Geometry · Mathematics 2021-09-20 Sun-Yung Alice Chang , Eric Chen

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

This article provides an attempt to extend concepts from the theory of Riemannian manifolds to piecewise linear spaces. In particular we propose an analogue of the Ricci tensor, which we give the name of an Einstein vector field. On a given…

Mathematical Physics · Physics 2016-05-04 Robert Schrader

Geodesics become an essential element of the geometry of a semi-Riemannian manifold. In fact, their differences and similarities with the (positive definite) Riemannian case, constitute the first step to understand semi-Riemannian Geometry.…

Differential Geometry · Mathematics 2010-03-23 Anna Maria Candela , Miguel Sánchez

A large class of initial-boundary value problems of linear evolution partial differential equations formulated on the half-line is analyzed via the unified transform method. In particular, explicit formulae are presented for the generalized…

Analysis of PDEs · Mathematics 2016-04-21 Athanassios S. Fokas , Zipeng Wang

We introduce a variation of the classical Ricci flow equation that modifies the unit volume constraint of that equation to a scalar curvature constraint. The resulting equations are named the Conformal Ricci Flow Equations because of the…

Differential Geometry · Mathematics 2009-11-10 Arthur E. Fischer

We propose a new approach to the theory of normal forms for Hamiltonian systems near a non-resonant elliptic singular point. We consider the space of all Hamiltonian functions with such an equilibrium position at the origin and construct a…

Dynamical Systems · Mathematics 2023-06-27 Dmitry Treschev

Shape analysis and compuational anatomy both make use of sophisticated tools from infinite-dimensional differential manifolds and Riemannian geometry on spaces of functions. While comprehensive references for the mathematical foundations…

Differential Geometry · Mathematics 2018-07-31 Martins Bruveris

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

We propose a solution to the problem of estimating a Riemannian metric associated with a given differentiable manifold. The metric learning problem is based on minimizing the relative volume of a given set of points. We derive the details…

Machine Learning · Computer Science 2012-12-12 Guy Lebanon

The paper describes a new approach to global smoothing problems for inhomogeneous dispersive evolution equations based on an idea of canonical transformation. In our previous papers, we introduced such a method to show global smoothing…

Analysis of PDEs · Mathematics 2015-10-16 Michael Ruzhansky , Mitsuru Sugimoto

In this chapter we take up the quantum Riemannian geometry of a spatial slice of spacetime. While researchers are still facing the challenge of observing quantum gravity, there is a geometrical core to loop quantum gravity that does much to…

General Relativity and Quantum Cosmology · Physics 2023-02-07 Hal M. Haggard , Jerzy Lewandowski , Hanno Sahlmann

We investigate the existence and uniqueness of solutions for second-order semi-linear partial differential equations defined on a Riemannian manifold $M$. By combining differential geometry and analysis techniques, we establish the…

Analysis of PDEs · Mathematics 2025-07-16 Nicolas Martinez-Alba , Oscar Riaño

The Hamiltonian approach to the theory of dual isomonodromic deformations is developed within the framework of rational classical R-matrix structures on loop algebras. Particular solutions to the isomonodromic deformation equations…

solv-int · Physics 2009-10-30 J. Harnad