On Randers Metrics with Isotropic S-Curvature

In this paper, we study a class of Finsler metrics defined by a vector field on a Riemannian space form. We give an explicit formula for those with isotropic S-curvature. This class contains all Randers metrics of constant flag curvature.

PROJECTIVELY FLAT FINSLER METRICS WITH ALMOST ISOTROPIC S-CURVATURE

This article characterizes projectively fiat Finsler metrics with almost isotropic S-curvature.

Navigation Finsler metrics on a gradient Ricci soliton

In this paper,we study a class of Finsler metrics defined by a vector field on a gradient Ricci soliton.We obtain a necessary and sufficient condition for these Finsler metrics on a compact gradient Ricci soliton to be of isotropic S-curvature by establishing a new integral inequality.Then we determine the Ricci curvature of navigation Finsler metrics of isotropic S-curvature on a gradient Ricci soliton generalizing result only known in the case when such soliton is of Einstein type.As its application,we obtain the Ricci curvature of all navigation Finsler metrics of isotropic S-curvature on Gaussian shrinking soliton.

On the Ricci Curvature of a Randers Metric of Isotropic S-curvature

We derive the integral inequality of a Randers metric with isotropic S-curvature in terms of its navigation representation. Using the obtained inequality we give some rigidity results under the condition of Ricci curvature. In particular, we show the following result： Assume that an n-dimensional compact Randers manifold （M, F） has constant S-curvature c. Then （M, F） must be Riemannian if its Ricci curvature satisfies that Ric 〈 -（n - 1）c^2.

On (α,β)-Metrics of Scalar Flag Curvature with Constant S-curvature

In this paper, we study （α,β）-metrics of scalar flag curvature on a manifold M of dimension n （n 〉 3）. Suppose that an （α,β）-metric F is not a Finsler metric of Randers type, that is, F ≠k1 V√α^2 ＋ k2β^2 ＋ k3β, where k1 〉 0, k2 and k3 are scalar functions on M. We prove that F is of scalar flag curvature and of vanishing S-curvature if metric. In this case, F is a locally Minkowski and only if the flag curvature K = 0 and F is a Berwald metric.

Homogeneous manifolds admitting non-Riemannian Einstein-Randers metrics

In this paper, we find some new homogeneous manifolds G/H admitting non-Riemannian EinsteinRanders metrics when G is the compact simple Lie group E6, or E7 or E8. In the beginning, we prove that these homogeneous manifolds admit Riemannian Einstein metrics. Based on these metrics, we obtain non-Riemannian Einstein Randers metrics on them.

NATURALLY REDUCTIVE(α_(1),α_(2))METRICS

Letting F be a homogeneous(α_(1),α_(2))metric on the reductive homogeneous manifold G/H,we first characterize the natural reductiveness of F as a local f-product between naturally reductive Riemannian metrics.Second,we prove the equivalence among several properties of F for its mean Berwald curvature and S-curvature.Finally,we find an explicit flag curvature formula for G/H when F is naturally reductive.

Projective Changes between Generalized (<i>α</i>, <i>β</i>)-Metric and Randers Metric

Projective change between two Finsler metrics arises from Information Geom-etry. Such metrics have special geometric properties and will play an important role in Finsler geometry. The purpose of the present paper is to find a relation to characterize the projective change between generalized (α, β) - metric ( μ1, μ2 and μ3 ≠ 0 are constants) and Randers metric , where α and are two Riemannian metrics, β and are 1-forms. Further, we study such projective change when generalized (α, β) -metric F has some curvature property.

局部对偶平坦的Randers度量

研究Randers度量F=α+β(其中α是黎曼度量,β是1-形式)的局部对偶平坦问题.得到了当α是局部射影平坦时F是局部对偶平坦的充要条件.

反正切Finsler度量与Randers度量射影等价(英文)

本文研究了反正切Finsler度量F=α+εβ+βarctan(β/α)与Randers度量F=α+β射影等价,这里α和α表示流形上的两个黎曼度量,β和β表示流形上的两个非零的1-形式.利用射影等价具有相同的Douglas曲率的性质,获得了这两类度量射影等价的充要条件.

具有标量曲率的Randers流形

文中主要研究了具有曲率的一类特殊的芬斯勒流形——Randers流形。首先回顾了芬斯勒流形的基本知识及芬斯勒流形的导航问题的有关事实。进一步通过对导航问题的研究转化为将Randers流形转化为黎曼流形的研究,利用Schur引理,证明了Randers流形具有标量旗曲率当且仅当该流形具有常曲率这一性质。

局部对偶平坦的Randers度量

该文研究了形如F=α+β的Randers度量的性质,得到了局部对偶平坦的Randers度量的充要条件.同时刻画了当α具有常数曲率或β为闭的1-形式时的Randers度量.

局部对偶平坦的平方Randers度量

研究了形如F=(α+αβ)2的平方Randers度量,其中α=aijyiyj,β=biyi是1-形式.分别得到了平方Randers度量在α具有常曲率或β是闭的情形时的局部对偶平坦的充分必要条件.

齐性空间上的正则Einstein-Randers度量

本中主要研究了齐性空间上不变正则Einstein-Randers度量。首先回顾了李群李代数的基本知识和齐性空间的基本事实。进一步将几何问题转换为相应的代数问题,通过对李群李代数的研究,将代数结果几何化,得出相应的几何结论,以便达到研究几何的目的。最后证明了齐性空间上任何不变正则Einstein-Randers度量一定是黎曼度量这一刚性结论。

具有迷向S曲率Randers度量的几何意义(英文)

Riemann流形上的Zermelo航行为Randers度量提供了一个简洁而且清晰的几何背景．在这个背景下D．Bao,C．Robles和Z．Shen对于具有常旗曲率的Randers度量进行了完全分类．这篇论文中,我得到了判定具有特殊曲率性质的Randers度量的两个充分必要条件．从这两个条件出发,我得到了迷向S曲率的Randers度量的几何意义和一系列推论,并且构造了具有迷向S曲率Randers度量的新例子．最后,在Zermelo航行的背景下研究了Berwald型的Randers度量．

射影相关于Randers度量的(α,β)-度量

(α,β)-度量是Finsler几何中非常重要的一类度量,Randers度量是最简单的非黎曼的(α,β)-度量.近年来,很多学者研究了具有特定形式的(α,β)-度量与Randers度量的射影相关问题[1-3],本文将特定形式的(α,β)-度量推广为一般的(α,β)-度量,研究了其与Randers度量的射影相关,得到了它们射影相关的充要条件.

构造具有特殊性质的复Randers度量

首先证明了当||β||α<1时,复Randers度量的Cartan挠率具有上界.然后推导出所构造的含有3个参数的复Randers度量要么是非弱Khler Finsler度量,要么满足βb0|0+βb0|0≠0,并且该度量具有一致上界.最后给出一些例子说明如果ρ2+λε=0,那么它们的全纯曲率都是非正的.

一类Randers度量(英文)

研究了一类特殊的Randers度量,找到了这类度量与黎曼度量α逐点射影等价的几个方程.

On a class of two-dimensional Finsler manifolds of isotropic S-curvature

For an(α, β)-metric(non-Randers type) of isotropic S-curvature on an n-dimensional manifold with non-constant norm ‖β‖α, we first show that n = 2, and then we characterize such a class of two-dimensional(α, β)-manifolds with some PDEs, and also construct some examples for such a class.

ON(α,β)-METRICS OF CONSTANT FLAG CURVATURE

In this paper,we study the(α,β)-metrics of constant flag curvature.We characterize almost regular(α,β)-metrics of constant flag curvature under the condition that β is a homothetic 1-form with respect to a.Furthermore,we prove that if a regular(α,β)-metric is of constant flag curvature and β is a Killing 1-form with constant length,then it must be a Riemannian metric or locally Minkowskian.