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A classical theorem of Bochner asserts that the isometry group of a compact Riemannian manifold with negative Ricci curvature is finite. In this paper we give several extensions of Bochner's theorem by allowing "small" positive Ricci…

Differential Geometry · Mathematics 2022-08-04 Xiaoyang Chen , Fei Han

We show that any transversally complete Riemannian foliation F of dimension one on any possibly non-compact manifold M is tense; namely, (M,F) admits a Riemannian metric such that the mean curvature form of F is basic. This is a partial…

Differential Geometry · Mathematics 2013-09-30 Hiraku Nozawa , José Ignacio Royo Prieto

This is Part II of a series on noncompact isometry groups of Lorentz manifolds. We have introduced in Part I, a compactification of these isometry groups, and called ``bi-polarized'' those Lorentz manifolds having a ``trivial ''…

dg-ga · Mathematics 2016-08-31 Abdelghani Zeghib

In this paper angular curvature measures are investigated. Our first result is a complete classification of translation-invariant angular smooth curvature measures on $\mathbb{R}^n$. Subsequently, we use this result to show that the class…

Differential Geometry · Mathematics 2019-08-15 Thomas Wannerer

Motivated by recent interest concerning "puncture repair" in the conformal geometry of compact Riemannian manifolds, a brief exposition on generalisation to the setting of quasiconformal mappings on certain metric measure spaces is…

Complex Variables · Mathematics 2018-10-02 Ben Warhurst

This paper investigates the question of which smooth compact 4-manifolds admit Riemannian metrics that minimize the L2-norm of the curvature tensor. Metrics with this property are called OPTIMAL; Einstein metrics and scalar-flat…

Differential Geometry · Mathematics 2007-05-23 Claude LeBrun

We investigate the convergence of the mean curvature flow of arbitrary codimension in Riemannian manifolds with bounded geometry. We prove that if the initial submanifold satisfies a pinching condition, then along the mean curvature flow…

Differential Geometry · Mathematics 2012-04-03 Kefeng Liu , Hongwei Xu , Entao Zhao

The notion of nonpositive curvature in Alexandrov's sense is extended to include p-uniformly convex Banach spaces. Infinite dimensional manifolds of semi-negative curvature with a p-uniformly convex tangent norm fall in this class on…

Differential Geometry · Mathematics 2014-02-26 Cristian Conde , Gabriel Larotonda

Using a method introduced by R. Bamler to study the behavior of scalar curvature under continuous deformations of Riemannian metrics, we prove that if a sequence of smooth Riemannian metrics gi on a fixed compact manifold M has isotropic…

Differential Geometry · Mathematics 2018-01-26 Thomas Richard

Our aim in this paper is to study local rigidity for metrics defined on a compact manifold $M$ with boundary satisfying constant scalar curvature on $M$ and constant mean curvature on $\partial M$. We present some geometrical hypotheses…

Differential Geometry · Mathematics 2015-08-05 Sandra C. García-Martinez , J. Herrera

The probability distribution $\mu_{cl}$ of a general cluster point process in a Riemannian manifold $X$ (with independent random clusters attached to points of a configuration with distribution $\mu$) is studied via the projection of an…

Functional Analysis · Mathematics 2011-09-29 Leonid Bogachev , Alexei Daletskii

We describe a construction of Riemannian metrics of nonnegative sectional curvature on a closed smooth nonorientable 4-manifold with fundamental group of order two that realizes a homotopy class that was not previously known to contain…

Differential Geometry · Mathematics 2018-12-14 Rafael Torres

On a Riemannian or a semi-Riemannian manifold, the metric determines invariants like the Levi-Civita connection and the Riemann curvature. If the metric becomes degenerate (as in singular semi-Riemannian geometry), these constructions no…

Differential Geometry · Mathematics 2017-01-31 Ovidiu Cristinel Stoica

We construct several examples of compactifications of Einstein metrics. We show that the Eguchi--Hanson instanton admits a projective compactification which is non--metric, and that a metric cone over any (pseudo)--Riemannian manifolds…

Differential Geometry · Mathematics 2020-02-12 Maciej Dunajski , A. Rod Gover , Alice Waterhouse

We define barycentric coordinates on a Riemannian manifold using Karcher's center of mass technique applied to point masses for n+1 sufficiently close points, determining an n-dimensional Riemannian simplex defined as a "Karcher simplex."…

Numerical Analysis · Mathematics 2016-10-06 Stefan W. von Deylen , David Glickenstein , Max Wardetzky

This is a survey of recent results on manifolds with positive curvature from a series of lecture given in Guanajuato, Mexico in 2010. It also contains some hitsorical comments.

Differential Geometry · Mathematics 2012-10-16 Wolfgang Ziller

In this article, we examine the behavior of the Riemannian and Hermitian curvature tensors of a Hermitian metric, when one of the curvature tensors obeys all the symmetry conditions of the curvature tensor of a K\"ahler metric. We will call…

Differential Geometry · Mathematics 2023-03-31 Bo Yang , Fangyang Zheng

We study the canonical metric on a compact Riemann surface of genus at least two. While it is known that the canonical metric is of nonpositive curvature, we show that its Gaussian curvatures are not bounded away from zero nor negative…

Differential Geometry · Mathematics 2007-05-23 Zheng Huang

In this paper we provide new necessary and sufficient conditions for the existence of K\"ahler-Einstein metrics on small deformations of a Fano K\"ahler-Einstein manifold. We also show that the Weil-Petersson metric can be approximated by…

Differential Geometry · Mathematics 2024-03-12 Huai-Dong Cao , Xiaofeng Sun , Shing-Tung Yau , Yingying Zhang

We establish the extrinsic Bonnet-Myers Theorem for compact Riemannian manifolds with positive Ricci curvature. And we show the almost rigidity for compact hypersurfaces, which have positive sectional curvature and almost maximal extrinsic…

Differential Geometry · Mathematics 2025-05-27 Weiying Li , Guoyi Xu