On Pseudo-Holomorphic Curves from Two-Spheres into a Complex Grassmannian G（2, 5）

Let s ： S2 → G（2, 5） be a linearly full totally unramified pseudo-holomorphic curve with constant Gaussian curvature K in a complex Grassmann manifold G（2, 5）. It is prove that K is either 1 4 1 or 4/5 if s is non-±holomorphic. Furthermore, K = 1/3 if and only if s is totally real. We also prove that the Gaussian curvature K is either 1 or -4/3 if s is a non-degenerate holomorphic curve under some conditions.     

图胞映射的一种改进方法

通过引入新的概念，提出了图胞映射动力系统中瞬态胞的新的分类方法，基于新的分类方法研究了动力系统中不变流形的胞映射逼近问题；并结合计算机的计算速度与内存特点，建立了完成上述压缩分类的有效算法.通过对典型算例Henon映射的应用分析，证实了该方法的有效性.     

VARIATIONAL PROPERTIES OF THE INTEGRATED MEAN CURVATURES OF TUBES IN SYMMETRIC SPACES

61. IntroductionLet P be a submanifold of an n-dimensional riemannian manifold AI. Expressions fOrthe kth integrated mean curvatures, M^P(t), (i. e. the integral of tho kth mcan curvature,k = 0, 1,' l n -- l), of a tubular hypersurface P of radius t about P, in terms of theRiemann curvature tensor of P. are calculated when AI is Euclidean or a rank one symmetricspace[5'13"1. Moreover, when P is a closed convex hypersurface of thc n-dimensional spaceof constant curvature A', Santal6 has…     

ON NONLINEAR DIFFERENTIAL GALOIS THEORY

This Is an accom ofa work In course ofprogress．The aim Is the following:     

非定空间形式Nn+pp(c)中常数量曲率的类空子流形

利用一个类似于CHENG等引进的微分算子的新微分算子□α(α=n+1,…,n+p),得到了非定空间形式Nn+pp(c)中常数量曲率的紧致的类空子流形的一个刚性定理设Mn是非定空间形式Nn+pp(c)(p＞1)中标准数量曲率R为常数的n维(n＞2)紧致的类空子流形,且标准平均曲率向量关于法联络平行,如果=R-1,-1＜≤0且Mn的第2基本形式的模长平方|B|2满足-n≤|B|2≤C(,p,n),这里C(,p,n)为只依赖于,p和n的某一常数,则|B|2=-n且Mn为全脐子流形.我们把CHENG(1977),LI(1996)的结果推广到了非定空间形式中常数量曲率的类空子流形中.由于我们在定理中去掉了"平坦法丛"的条件,所以本文的讨论优于HOU(1998)的讨论.     

NOETHERIAN GR-REGULAR RINGS ARE REGULAR

It is proved that for a left Noetherian z-graded ring A,if every finitely generated graded A-module has finite projective dimension(i.e-,A is gr-regular)then every finitely generated A-module has finite projective dimension(i.e.,A is regular).Some applications of this result to filtered rings and some classical cases are also given.     

推广的Painlevé展开及KdV方程的非标准截断解

利用奇性流形的任意性，选用不同的展开函数及非标准截断展开于KdV方程，得到了许多用复杂隐函数表示的精确解. 关键词：     

G2,n中的可兼共形调和曲面

本文通过建立复Ｇｒａｓｓｍａｎｎ流形Ｇ２，ｎ中调和曲面的Ｇａｕｓｓ丛的基本公式，在适当的拓扑条件下给出了Ｇ２，ｎ中可兼共形调和曲面的构造定理．推广和改进了Ｂｕｒｓｔａｌｌ和Ｗｏｏｄ的低亏格曲面的结果．     

日观测到快速成长的巨大星体

 据《中国科学报》报道 日本国立天文台和东京大学的一个研究小组最近首次观测到一个正在快速成长的巨大原始星体.     

2—Harmonic Totally Real Submanifolds in a Complex Projective Space

２－ＨａｒｍｏｎｉｃＴｏｔａｌｌｙＲｅａｌＳｕｂｍａｎｉｆｏｌｄｓｉｎａＣｏｍｐｌｅｘ　Ｐｒｏｊｅｃｔｉｖｅ　ＳｐａｃｅＳｕｎＨｏｎｇａｎ（孙弘安）（ＳｏｕｔｈｅｒｎＩｎｓｔｉｔｕｔｅｏｆＭｅｔａｌｌｕｒｇｙ）Ａｂｓｔｒａｃｔ：Ｉｎｔｈｉｓｐａｐｅｒ...