SECTIONAL CURVATURE OF KAEHLER SUBMANIFOLDS OF A COMPLEX PROJCETIVE SPACE

Let M~n (n≥2) be a complex Kaehler submanifold immersed in the complex projective space CP~m(1). Let K be the sectional curvature of M~n. Then K≥1/8 if and only if M~n is an imbedding submanifold congruent to the standard imbedding CP~n (1) or CP~n(1/2).     

具非负Ricci曲率和严格（1＋δ）阶体积增长的三维流形

本文研究了三维完备非紧具非负Ricci曲率的黎曼流形的几何拓扑性质.通过对流形本身与流形的万有覆盖空间体积增长阶的比较,证明了对具非负Ricci曲率和严格(1+δ)阶体积增长的三维完备非紧的黎曼流形是可缩的.     

球面的平行平均曲率子流形

本文讨论单位球面中具有平行单位平均曲率向量的子流形的第二基本形式长度拼挤问题,改进了已有的结论。     

SUBMANIFOLDS WITH PARALLEL MEAN CURVATURE AND GAUSS MAPS

The aim of this paper is to study the relations between submanifolds with parallel mean curvature and their Gauss maps, and in virtue of them we obtain three main theorems. They show some geometrical restrictions to a submanifold of Euclidean space E~n with parallel mean curvature.     

ON COMPLETE SPACE-LIKE SUBMANIFOLDS WITH PARALLEL MEAN CURVATURE VECTOR

§１．ＩｎｔｒｏｄｕｃｔｉｏｎＬｅｔＮｎ＋ｐｐｂｅａｎ（ｎ＋ｐ）－ｄｉｍｅｎｓｉｏｎａｌｃｏｎｎｅｃｔｅｄｐｓｅｕｄｏ－Ｒｉｅｍａｎｎｉａｎｍａｎｉｆｏｌｄｏｆｉｎｄｅｘｐ．ＩｆＮｎ＋ｐｐｉｓｃｏｍｐｌｅｔｅａｎｄｈａｓｃｏｎｓｔａｎｔｓｅｃｔｉｏｎ...     

GLOBAL RIGIDITY THEOREMS FOR SUBMANIFOLDS WITH PARALLEL MEAN CURVATURE

In this paper,we mainly study the global rigidity theorem of Riemannian submanifolds in space forms.Let Mⁿ(n≥3) be a complete minimal submanifold in the unit sphere S^n+p(1).For λ∈ [0,n/(2-1/p)),there is an explicit positive constant C(n,p,λ),depending only on n,p,λ,such that,if ∫_M S^n/2dM<∞,∫_M(S-λ)₊^n/2 dM 相似文献   

具有非负Ricci曲率和次大体积增长的完备流形(英文)

本文研究了具有非负Ricci曲率和次大体积增长的完备黎曼流形的拓扑结构问题.利用Toponogov型比较定理及临界点理论,获得了流形具有有限拓扑型的结果,推广了H.Zhan和Z.Shen的定理,并且还证明了该流形的基本群是有限生成的.     

常曲率空间中的具有共形第二基本形式的子流形

以把调和态射看作等距浸入的单位法投影的问题为背景,研究了具有共形第二基本形式的子流形,论证了具有共形第二基本形式的高维子流形,一般不是由极小点和全脐点构成,这和曲面的情形形成了鲜明的对照。也给出了常曲率空间中具有平行中曲率的奇数维子流形的一个完全分类。     

ON THE FUNDAMENTAL GROUP OF OPEN MANIFOLDS WITH NONNEGATIVE RICCI CURVATURE＊＊＊＊

The authors establish some uniform estimates for the distance to halfway points of minimal geodesics in terms of the distantce to end points on some types of Riemannian manifolds, and then prove some theorems about the finite generation of fundamental group of Riemannian manifold with nonnegative Ricci curvature, which support the famous Milnor conjecture.     

HARMONIC FUNCTIONS ON A COMPLETE NONCOMPACT MANIFOLD WITH ASYMPTOTICALLY NONNEGATIVE CURVATURE

The authors prove the space of harmonic functions with polynomial growth of a fixed rate on a complete noncompact Riemannian manifold with asymptotically nonnegative curvature is finite dimensional.     

常曲率空间中的具有共形第二基本形式的子流形

以把调和态射看作等距浸入的单位法投影的问题为背景,研究了具有共形第二基本形式的子流形,论证了具有共形第二基本形式的高维子流形,一般不是由极小点和全脐点构成.这和曲面的情形形成了鲜明的对照.也给出了常曲率空间中具有平行中曲率的奇数维子流形的一个完全分类.     

复空间形式中具有常数量曲率的全实子流形

本文研究了复空间形式中具有常数量曲率的全实子流形.利用一种自伴算子,得到了这类子流形关于第二基本形式模长平方的积分不等式.     

复射影空间中具有平行平均曲率向量的一般子流形

本文研究了复射影空间中具有平行平均曲率向量的一般子流形曲率性质与几何性质之间的关系. 利用活动标架法, 获得了关于截面曲率, Ricci 曲率和第二基本形式模长的刚性定理, 推广和完善了相关文献的若干结果.     

非正曲率流形及其子流形上有界区域的特征值

本文研究了完备单连通具有非正曲率黎曼流形及其子流形上有界区域的特征值问题.利用广义Hessian比较定理,获得了局部特征值的下界估计式,将McKean[2]的定理在局部上推广到了非正曲率的情形.     

DARBOUX EQUATIONS AND ISOMETRIC EMBEDDING OF RIEMANNIAN MANIFOLDS WITH NONNEGATIVE CURVATURE IN R^3

The present paper is concerned with the existence of golbal smooth solutions for the homogeneous Dirichlet boundary value problem of the Darboux equation and the case degenerate on the boundary is contained. As some applications the smooth isometric embeddings of positively and nonnegatively curved disks into Rs are constructed.     

FATOU PROPERTY ON HARMONIC MAPS FROM COMPLETE MANIFOLDS WITH NONNEGATIVE CURVATURE AT INFINITY INTO CONVEX BALLS

ＦＡＴＯＵＰＲＯＰＥＲＴＹＯＮＨＡＲＭＯＮＩＣＭＡＰＳＦＲＯＭＣＯＭＰＬＥＴＥＭＡＮＩＦＯＬＤＳＷＩＴＨＮＯＮＮＥＧＡＴＩＶＥＣＵＲＶＡＴＵＲＥＡＴＩＮＦＩＮＩＴＹＩＮＴＯＣＯＮＶＥＸＢＡＬＬＳ￥ＹＡＮＧＹＩＨＵＡｂｓｔｒａｃｔ：Ｔｈｅａｕｔｈｏｒｃ...     

THE GAUSS MAP OF SUBMANIFOLDSIN SPACES OF CONSTANT CURVATURE

ＴＨＥＧＡＵＳＳＭＡＰＯＦＳＵＢＭＡＮＩＦＯＬＤＳＩＮＳＰＡＣＥＳＯＦＣＯＮＳＴＡＮＴＣＵＲＶＡＴＵＲＥ￥ＺＨＯＵＪＩＡＮＷＥＩＡｂｓｔｒａｃｔ：ＴｈｉｓｐａｐｅｒｓｔｕｄｉｅｓｔｈｅＧａｕｓｓｍａｐｏｆｓｕｂｍａｎｉｆｏｌｄｓｉｎｓｐａｃｅｆｏｒｍ...     

MINIMAL SUBMANIFOLDS IN A RIEMANNIAN MANIFOLD OF QUASI CONSTANT CURVATURE

A Riemannian manifold V~m which admits isometric imbedding into two spaces V~(m+p)ofdifferent constant curvatures is called a manifold of quasi constant curvature.TheRiemannian curvature of V~m is expressible in the formand conversely.In this paper it is proved that if M~n is any compact minimal submanifoldwithout boundary in a Riemannian manifold V~(n+p)of quasi constant curvature,then∫_(M~u)(2-1/p)σ~2-[na+1/2(b-丨b丨)(n+1)]σ+n(n-1)b~2*丨≥0,where σ is the square of the norm of the second fundamental form of M~n When V~(n+p)is amanifold of constant curvature,b=0,the above inequality reduces to that of Simons.     

关于极小子流形全纯量曲率的一个空隙定理

本文证明了欧氏空间RN中的n-维(n＞2)完备极小子流形,若其全纯量曲率小于(π/4@√6)n,则必是n-维平面.此结论改进了文[2,6]中的结果.