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相关论文: Remarks on $\eta$-Einstein unit tangent bundles

200 篇论文

We prove a Theorem on homotheties between two given tangent sphere bundles $S_rM$ of a Riemannian manifold $M,g$ of $\dim\geq 3$, assuming different variable radius functions $r$ and weighted Sasaki metrics induced by the conformal class of…

微分几何 · 数学 2019-07-25 Rui Albuquerque

In this article, we study quasi-Einstein manifolds with constant scalar curvature. We provide a classification of compact and noncompact (possibly with boundary) $T$-flat quasi-Einstein manifolds with constant scalar curvature, where the…

微分几何 · 数学 2025-05-27 Johnatan Costa , Ernani Ribeiro , Márcio Santos

We consider homogeneous hypercomplex manifolds with a transitive action of a compact Lie group and we give a characterization of invariant HKT metrics on them. On every such hypercomplex manifold we prove the existence of an invariant…

微分几何 · 数学 2026-04-27 Lucio Bedulli , Lorenzo Marcocci

In the following work we investigate the structure of Einstein manifolds with positive scalar curvature whose curvature operator is sufficiently close to the identity operator in dimensions below 12. An Einstein manifold with positive…

微分几何 · 数学 2023-11-07 Kevin Poljsak

The existence or non-existence of Einstein metrics on 4-manifolds with non-trivial fundamental group and the relation with the underlying differential structure are analyzed. For most points $(n,m)$ in a large region of the integer lattice,…

微分几何 · 数学 2016-10-11 Ioana Suvaina

A weakly Einstein manifold is a generalization of a 4-dimensional Einstein manifold, which is defined as an application of a curvature identity derived from the generalized Gauss-Bonnet formula for a 4-dimensional compact oriented…

微分几何 · 数学 2010-10-20 Y. Euh , J. H. Park , K. Sekigawa

We prove that a Gaussian ensemble of smooth random sections of a real vector bundle over compact manifold canonically defines a metric on the bundle together with a connection compatible with it. Additionally, we prove a refined…

概率论 · 数学 2015-04-29 Liviu I. Nicolaescu

In this work, we investigate the geometry and topology of compact Einstein-type manifolds with nonempty boundary. First, we prove a sharp boundary estimate, as consequence we obtain under certain hypotheses that the Hawking mass is bounded…

微分几何 · 数学 2022-04-27 Maria Andrade , Ana Paula de Melo

This paper attempts to define a generalisation of the standard Einstein condition (in conformal/metric geometry) to any parabolic geometry. To do so, it shows that any preserved involution $\sigma$ of the adjoint bundle $\mc{A}$ gives rise,…

微分几何 · 数学 2008-08-14 Stuart Armstrong

The object of the present paper is to study some properties of Kenmotsu manifold whose metric is conformal $\eta$-Einstein soliton. We have studied some certain properties of Kenmotsu manifold admitting conformal $\eta$-Einstein soliton. We…

微分几何 · 数学 2021-06-09 Soumendu Roy , Santu Dey , Arindam Bhattacharyya

In this paper, we establish compactness results of some class of conformally compact Einstein 4-manifolds. In the first part of the paper, we improve the earlier results obtained by Chang-Ge. In the second part of the paper, as…

微分几何 · 数学 2019-07-15 Sun-Yung A. Chang , Yuxin Ge , Jie Qing

Given a closed contact 3-manifold with a compatible Riemannian metric, we show that if the sectional curvature is 1/4-pinched, then the contact structure is universally tight. This result improves the Contact Sphere Theorem in [EKM12],…

微分几何 · 数学 2013-04-19 Jian Ge , Yang Huang

We examine several classes of manifolds which have the same cohomology ring as an Eschenburg space (a family of biquotients which is a main source of manifolds with positive curvature). One family are the 3-sphere bundles over CP^2. Another…

微分几何 · 数学 2012-06-27 Christine Escher , Wolfgang Ziller

Peng Wu recently announced a beautiful characterization of conformally Kaehler, Einstein metrics of positive scalar curvature on compact oriented 4-manifolds via the condition det (W^+) > 0. In this note, we buttress his claim by providing…

微分几何 · 数学 2019-09-24 Claude LeBrun

We derive the general formulas for a special configuration of the sequential warped product semi-Riemannian manifold to be Einstein, where the base-manifold is the product of two manifolds both equipped with a conformal metrics.…

In this note, we show that a nontrivial, compact, degenerate or nondegenerate, gradient Einstein-type manifold of constant scalar curvature is isometric to the standard sphere with a well defined potential function. Moreover, under some…

微分几何 · 数学 2021-05-04 José Nazareno Vieira Gomes

Given a manifold with boundary, one can consider the space of subsurfaces of this manifold meeting the boundary in a prescribed fashion. It is known that these spaces of subsurfaces satisfy homological stability if the manifold has at least…

代数拓扑 · 数学 2020-09-02 Thorben Kastenholz

In this work we wish characterize the Einstein manifolds $(M,g)$, however without the necessity of hypothesis of compactness over $M$ and unitary volume of $g$, which are well known in many works. Our result says that if all eingenvalues…

微分几何 · 数学 2013-05-27 S. N. Stelmastchuk

In this paper, we deduce a Bochner-type identity for compact gradient Einstein-type manifolds with boundary. As consequence, we are able to show a rigidity result for Einstein-type manifolds assuming the parallel Ricci curvature condition.…

微分几何 · 数学 2024-03-06 Maria Andrade , Halyson Baltazar , Christopher Queiroz

A rigidity result for a class of compact generalized quasi-Einstein manifolds with constant scalar curvature is obtained. Moreover, under some geometric assumptions, the rigidity for the noncompact case is also proved. Considering non…

微分几何 · 数学 2021-12-09 Antonio Airton Freitas Filho , Keti Tenenblat