具有可反Douglas曲率的Matsumoto度量（英文）

本文得到Matsumoto度量具有可反Douglas曲率的充分必要条件,该条件蕴含存在具有可反Douglas曲率的非Douglas的Finsler度量.     

具有可反测地线的$(alpha,beta)$-度量

本文我们得到了$(alpha,beta)$-度量的测地系数$G^{i}(x,y)$和其逆$G^{i}(x,-y)$有相同Douglas曲率的充分必要条件.这个充分必要条件恰好是$(alpha,beta)$-度量具有可反测地线的充分必要条件.     

R^n空间上具有正曲率和负曲率的度量一些例子

From the class of conformally flat metric of gij=f(|x|^2)δij defined on R^n,where f:[0,∞]→（0,∞）is a C^2 function,we find one class of metrics with positive curvature and two classes of complete metrics with negative curvature.     

具有迷向S曲率Randers度量的几何意义

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Raiders度量．     

一类具有标量旗曲率的Berwald(α,β)-度量(英文)

本文研究了一类具有F=α+εβ+kα²/β形式的Finsler度量,其中α=（aijyⁱy^j）^1/2是Riemann度量,β=b_iyⁱ是非零1-形式,ε和k≠0是常数。得到了这个Finsler度量的S曲率消失和成为弱Berwald度量的充要条件。另外通过证明发现具有标量期曲率的Finsler度量成为弱Berwald度量的充要条件是它们成为Berwald度量,并且期曲率消失。在这种情况下,该Finsler度量就是局部Minkowski度量。     

关于（α，β）-度量的S-曲率

给出（α，β）-度量F=αФ（α，β）的S-曲率的计算公式．证得对一般的（α，β）-度量，当β为关于α长度恒定的Killing1-形式时，S=0．研究了Matsumoto-度量F=α^2／（α-β）和（α，β），度量F=α＋εβ＋κ（β^2／α）的S-曲率，证得S=0当且仅当β为关于α长度恒定的Killing1-形式．同时还得到这两类度量成为弱Berwald度量的充要条件,其中Ф（s）为光滑函数，α（y）=√aij（x）y^iy^j为黎曼度量，β（y）=bi（x）y^i为非零1-形式且ε，κ≠0为常数．     

关于广义(α,β)-度量的若干Ricci曲率性质

本文研究了广义(α,β)-度量的Ricci曲率和Ricci曲率张量.首先,在一定条件下,本文给出了强Einstein广义(α,β)-度量的一个等价刻画.进一步,得到了广义(α,β)-度量是Ricci-齐次Finsler度量的一个充分必要条件.     

两类Cartan张量有界的(α,β)-度量（英文）

本文研究了两类重要的(α,β)-度量-(广义)Kropina度量和Matsumoto度量的Cartan张量.证明了这两类(α,β)-度量的Cartan张量是有界的,并由此给出了这两类度量的一些刚性结果及其应用.     

半对称度量循环联络的某些特征及曲率张量表示

The projective transformation of the special semi-symmetric metric recurrent connection is studied in this paper. First of all, an invariant under this transformation is granted; Secondly, by inducing of the invariant and making use of the properties that the corresponding covariant derivative keeps being fixed under the distinctness connection, the curvature tensor expression of the Riemannian manifold is posed at the same time.     

On Einstein Matsumoto metrics

Einstein metrics are solutions to Einstein field equation in General Relativity containing the Ricci-flat metrics. Einstein Finsler metrics which represent a non-Riemannian stage for the extensions of metric gravity, provide an interesting source of geometric issues and the (α,β)-metric is an important class of Finsler metrics appearing iteratively in physical studies. It is proved that every n-dimensional (n≥3) Einstein Matsumoto metric is a Ricci-flat metric with vanishing S-curvature. The main result can be regarded as a second Schur type Lemma for Matsumoto metrics.     

A generalization of 4-dimensional locally conformal flat Walker manifolds

A 4-dimensional Walker metrics with c = 0 on a semi-Riemannian manifold M have been investigated by E. García-Río and Y.Matsushita. The case c=constant has been studied in [1]. In this paper we generalize these notions to the case of non-constant c. We find the form of the defining functions that makes this manifold similar to locally conformal flat 4-dimensional Walker manifold.     

On Douglas general (<Emphasis Type=\"Italic\">α</Emphasis>, <Emphasis Type=\"Italic\">β</Emphasis>)-metrics

Douglas metrics are metrics with vanishing Douglas curvature which is an important projective invariant in Finsler geometry. To find more Douglas metrics, in this paper we consider a class of Finsler metrics called general (α, β)-metrics, which are defined by a Riemannian metric (alpha = sqrt {{a_{ij}}left( x right){y^i}{y^j}} ) and a 1-form β = b _i (x)y ⁱ . We obtain the differential equations that characterizes these metrics with vanishing Douglas curvature. By solving the equivalent PDEs, the metrics in this class are totally determined. Then many new Douglas metrics are constructed.     

On spherically symmetric Finsler metrics with vanishing Douglas curvature

We obtain the differential equation that characterizes the spherically symmetric Finsler metrics with vanishing Douglas curvature. By solving this equation, we obtain all the spherically symmetric Douglas metrics. Many explicit examples are included.     

Rigidity of conformally compact manifolds with the round sphere as the conformal infinity

In this paper, we prove that under a lower bound on the Ricci curvature and an assumption on the asymptotic behavior of the scalar curvature, a complete conformally compact manifold whose conformal boundary is the round sphere has to be the hyperbolic space. It generalizes similar previous results where stronger conditions on the Ricci curvature or restrictions on dimension are imposed.