首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
张廷枋 《数学研究》1995,28(3):74-80
本文用活动标架法证明了:仿射空间An+1中维数n大于2的非退化超曲面Mn,相对于诱导的仿射连络局部对称,当且仅当M是虚(improper)仿射球或者是非退化的二次超曲面.  相似文献   

2.
赵磊娜 《数学杂志》2017,37(6):1173-1176
本文研究了相关齐次函数的仿射球定理.利用Hopf极大值原理,对任意给定的带凹性条件的初等对称曲率问题,获得了此类仿射球定理.特别地,这也给出了Deicke齐次函数定理的一个新证明.  相似文献   

3.
摘要:设y:M→Rn+1是一个光滑连通流形到实仿射空间Rn+1的局部强凸浸入超曲面,而且是一个定义在区域Ω(?)Rn上的严格凸函数xn+1=f(x1,x2,…,xn)的图.在α相对法化下,相对抛物型仿射球满足一个四阶非线性偏微分方程组.本文证明了这类抛物型仿射球的一个新的Bernstein性质.  相似文献   

4.
Fubini-Pick形式关于Blaschke-Berwald度量(或中心仿射度量)平行的局部强凸等仿射(或中心仿射)超曲面分类问题,在过去十年内已被完全解决.文献[20]对Fubini-Pick形式关于Calabi度量平行的2,3维Calabi超曲面进行了分类,该文将其推广到4维的情形.  相似文献   

5.
张廷枋 《数学学报》2001,44(5):791-804
本文用活动标架法证明了:若 Mn(n≥2)是 n+1维仿射空间 An+1中非退化的仿射超曲面,(1)若■K=0(即差异张量平行),则M是仿射球,且J=0和G是一个Einstein度量,这里J是M的 Pick不变量,G是Blaschke度量;(2)R·K=0(即差异张量半平行)当且仅当S=0(M为虚仿射球),或者K=0(M为非退化的二次超曲面),这里 R为诱导仿射联络 ■的黎曼曲率算子.  相似文献   

6.
具有共变对称张量场的仿射超曲面   总被引:2,自引:1,他引:1  
张廷枋 《数学研究》1997,30(4):387-396
用活动标架法从不同方面证明并推广了文[2]的结果:(1)若Mn(n≥2)是n+1维仿射空间An 1中非退化的仿射超曲面,则2S共变对称(或R·S=0),当且仅当M是仿射球;(2)若Mn(n≥2)是An 1中非退化的仿射起曲面,则K共变对称当且仅当M是仿射球;若K和K都共变对称,则M是仿球,且J=0和仿射度量G是Einstein度量.  相似文献   

7.
关于A^3中仿射球面的两个定理   总被引:1,自引:0,他引:1  
杨文茂 《数学杂志》1993,13(2):243-249
本文讨论仿射凸曲面为仿射球面或其一部分的问题。利用椭圆型偏微分方程组解的唯一性定理(或称“拟解析函数法”),文中证明了两个较为广泛的定理(见定理1与2),它们进一步推广了诸如 H-定理,K-定理以及许多关于特殊的 Weingarten 曲面为仿射球面的定理。  相似文献   

8.
弱对称空间是对称空间的推广.本文讨论了一些特殊类型的弱对称空间的迷向表示,给出了带有约化的等距变换群的弱对称空间上的不变仿射联络.  相似文献   

9.
本文运用凸几何分析理论,建立了投影体的宽度积分和仿射表面积的一些新型Brunn-Minkowski不等式,这些结果改进了Lutwak的几个有用的定理.作为应用,进一步给出了混合投影体极的BrunnMinkowski型不等式.  相似文献   

10.
本文运用凸几何分析理论,建立了投影体的宽度积分和仿射表面积的一些新型Brunn-Minkowski 不等式,这些结果改进了Lutwak的几个有用的定理.作为应用,进一步给出了混合投影体极的Brunn- Minkowski型不等式.  相似文献   

11.
In this paper, continuing with Hu–Li–Vrancken and the recent work of Anti′c–DillenSchoels–Vrancken, we obtain a decomposition theorem which settled the problem of how to determine whether a given locally strongly convex affine hypersurface can be decomposed as a generalized Calabi composition of two affine hyperspheres, based on the properties of its difference tensor K and its affine shape operator S.  相似文献   

12.
The aim of this paper is to solve the Cauchy problem for locally strongly convex surfaces which are extremal for the equiaffine area functional. These surfaces are called affine maximal surfaces and here, we give a new complex representation which let us describe the solution to the corresponding Cauchy problem. As applications, we obtain a generalized symmetry principle, characterize when a curve in R3 can be a geodesic or pre-geodesic of a such surface and study the helicoidal affine maximal surfaces. Finally, we investigate the existence and uniqueness of affine maximal surfaces with a given analytic curve in its singular set.  相似文献   

13.
We prove a classification theorem for disk-homogeneous locally symmetric spaces.  相似文献   

14.
15.
Mark Wildon 《Journal of Algebra》2010,323(8):2243-2256
This paper studies the vertices, in the sense defined by J.A. Green, of Specht modules for symmetric groups. The main theorem gives, for each indecomposable non-projective Specht module, a large subgroup contained in one of its vertices. A corollary of this theorem is a new way to determine the defect groups of symmetric groups. The main theorem is also used to find the Green correspondents of a particular family of simple Specht modules; as a corollary, this gives a new proof of the Brauer correspondence for blocks of the symmetric group. The proof of the main theorem uses the Brauer homomorphism on modules, as developed by M. Broué, together with combinatorial arguments using Young tableaux.  相似文献   

16.
The distortion theorem for biholomorphic starlike mappings (with respect to origin )in bounded symmetric domains are given,The distortion theorem for locally biholomorphic convex mappings in bounded symmetric domains are given also.  相似文献   

17.
在Hausdorff局部凸拓扑线性空间中考虑约束集值优化问题(VP)的ε-强有效性.在内部锥类凸假设下,利用凸集分离定理,分别建立了关于ε-强有效解的标量化定理和ε-Lagrange乘子定理.  相似文献   

18.
Under the shrinking curvature flow with inner normal velocity V = kα(α > 1), it is shown that highly symmetric, locally convex initial curves evolve into a point asymptotically like an multi‐circles. The proof relies on a crucial use of Bonnensen inequality for highly symmetric, locally convex curves. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

19.
We show that there is a one to one correspondence between the set of semisimple locally symmetric spaces and the set of admissible square quadruplets. This correspondence leads to a new approach in the classification and a simple parametrization of irreducible locally symmetric spaces.  相似文献   

20.
A modular symbol is the fundamental class of a totally geodesic submanifold embedded in a locally Riemannian symmetric space , which is defined by a subsymmetric space . In this paper, we consider the modular symbol defined by a semisimple symmetric pair (G,G'), and prove a vanishing theorem with respect to the -component in the Matsushima-Murakami formula based on the discretely decomposable theorem of the restriction . In particular, we determine explicitly the middle Hodge components of certain totally real modular symbols on the locally Hermitian symmetric spaces of type IV. Received: December 8, 1996  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号