查询词典 Riemannian

In Riemannian manifolds, one studies Riemannian metric, covariant derivative, Riemannian connection, basic properties of the Riemann curvature tensor, curvature forms etc.

黎曼流形部分主要涉及黎曼度量，黎曼流形的定义，切向量场的协变微分，黎曼联络，黎曼几何的基本定理，曲率张量，曲率形式等概念和理论。

Endowed with a Riemannian metric derived from the gray scale information of a given image, the image space became a Riemannian manifold. On this Riemannian manifold, we evolved a curve by the mean curvature flow using the level set methods.

在图像空间上直接赋予一种由图像灰度信息导出的黎曼度量，使之成为黎曼流形，然后在此黎曼流形上利用水平集方法对曲线以平均曲率流进行演化。

The definitions of generalized directional derivative and generalized gradient of Lipschitz functions defined on Riemannian manifold are presented. Some properties of the directional derivative and gradient are proved by using tangent and cotangent mapping. The minimization necessary condition of nonsmooth Lipschitz functions is given. Moreover, Fritz John necessary optimality condition in mathematical programming is provided on Riemannian manifold.

在黎曼流形上给出了Lipschitz函数的广义方向导数和广义梯度的概念，利用黎曼流形局部上与欧氏空间开集微分同胚的性质以及切映射和余切映射导出了广义梯度的性质和运算法则，证明了定义在黎曼流形上的函数取得极小值的必要条件是广义梯度包含零元素，并利用这些性质给出了黎曼流形上数学规划问题的Fritz John型最优性条件。

Researches the submanifolds in nested space,for constant curvature Riemannian submanifold in quasi-constant curvature manifold and pseudo-umbilical submanifold with parallel mean curvature vector in constant curvature Riemannian submanifold,presents three sufficient conditions for this pseudo-umbilical submanifold to be total-umibilical submanifold,generalizes the result of JI Yongqiang.

对于拟常曲率流形中的常曲率黎曼子流形以及常曲率黎曼子流形中具有平行中曲率向量的紧致伪脐子流形，给出了这种伪脐子流形是全脐子流形的3个充分条件，推广了纪永强的相关结果。

At many occasions they arise quite natu-rally.For example,they appear in the Iwasawa decomposition of the isometry group ofa non-compact Riemannian symmetric space.Also,every connected homogeneous Rie-mannian manifold of non-positive sectional curvature can be represented as a connectedsolvable Lie group with a left-invariant Riemannian metric.

它们出现在非紧致黎曼对称空间的等距群的Iwasawa分解中；任一非正截面曲率的连通齐性和黎曼流形可以表为带有左不变黎曼度量的连通可解李群等，带有左不变黎曼度量的幂零及可解李群的微分几何，调和分析和谱几何是重要的研究课题。

For H-type groups, explicit equations of shortest sub-Riemannian geodesies and a full characterization of the sub-Riemannian isometry groups are given in this dissertation.

对广义的Heisenberg群，本论文给出了最短次黎曼测地线的明确表达方程，并完全刻画了次黎曼等距群。

F irst of all from global viewpoint we define a kind of nonlinear control systems on Riemannian manifold , and give the representation of state equation for the nonlinear systems under a local coordinate system of Riemannian manifold

首先从整体化的观点定义了一种建立在黎曼流形上的非线性控制系统，给出了系统的状态方程在黎曼流形的局部坐标系下的表达式

Nilpotent and solvable Lie groups with left-invariant Riemannian metrics play aremarkable role in Riemannian geometry.

在黎曼几何中，带有左不变黎曼度量的幂零和可解李群具有重要作用。

In the second part of this paper, by considering the geometric properties of some well-known classical Riemannian manifold and combining with results we had got, we give the definition of the parallel rays in a complete nocompact Riemannian manifold M, which are usual parallel rays when M is restricted to Euclidean space R.

本文的第二部分，基于对一些典型的黎曼流形几何性质的观察，结合已有的研究成果，我们首次给出了完备非紧黎曼流形上平行射线的定义，该定义在欧式空间中就是普通的平行射线。

In chapter 2 we recall the basic facts about Riemannian manifold and some notions of the transform theory on Riemannian manifolds.

首先，利用给定流形的向量丛上联络的存在性给出流形上的不可积分布上非完整联络的存在性证明，进而证明了次黎曼联络的存在唯一性，并以此为出发点研究了次黎曼流形中仿射变换、等距变换、共形变换和射影变换下的一些不变性质，给出了相应变换下的一些不变量。

In contrast to the ubiquitous rising-sun-with-rays military flag of the Japanese, Chinese banners and ensigns feature a range of designs.

与遍地都是的太阳军旗不同，中国人的旗帜和徽章设计得各式各样。

From their small corner of Feng's Guangzhou headquarters -- a jumble of pink leashes, squeezable rubber steaks, and plastic doggy Santas for Fido's stocking -- Soleil's designers come up with at least five new products a month.

从Feng 设在广州总部的产品展示柜台上可以看到，Soleil的设计师每月至少设计出5件新产品。