共查询到19条相似文献,搜索用时 46 毫秒
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中曲率大于零的非凸曲面 总被引:1,自引:1,他引:0
本文研究了曲面的曲率问题.利用积分几何方法和旋转曲面性质,构造出一个欧氏空间R3中紧致光滑的中曲率H大于零的非凸曲面,并得到了关于紧致光滑曲面曲率的几个不等式. 相似文献
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舒世昌 《纯粹数学与应用数学》2008,24(2)
研究了欧氏空间En p中具常数量曲率n(n-1)r的n(n>2)维完备连通子流形,得到了En p截面曲率非负且法联络平坦的完备连通子流形的一个分类定理. 相似文献
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研究了拟常曲率流形中具有平行平均曲率向量的子流形,给出了两个积分不等式. 相似文献
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常曲率空间中具平行平均曲率向量的子流形 总被引:6,自引:0,他引:6
本文利用第二基本形式的长度平方和平均曲率的关系研究常曲率空间中具平行平均曲率向量的子流形为全脐的pinching问题,获得了一定条件下的最佳pinching区间,并确定了phincning区间端点处对应非全脐子流形的分类. 相似文献
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YONGFAN Zheng 《Geometriae Dedicata》1997,67(3):295-300
Let M be a compact orientable submanifold immersed in a Riemannian manifold of constant curvature with flat normal bundle. This paper gives intrinsic conditions for M to be totally umbilical or a local product of several totally umbilical submanifolds. It is proved especially that a compact hypersurface in the Euclidean space with constant scalar curvature and nonnegative Ricci curvature is a sphere. 相似文献
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The main result of this paper states that the traceless second fundamental tensor A0 of an n-dimensional complete hypersurface M, with constant mean curvature H and finite total curvature, M |A0|n dvM < , in a simply-connected space form
(c), with non-positive curvature c, goes to zero uniformly at infinity. Several corollaries of this result are considered: any such hypersurface has finite index and, in dimension 2, if H
2 + c > 0, any such surface must be compact. 相似文献
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We give a complete classification of complete noncompact oriented surfaces with nonnegative Gaussian curvature and finite total mean curvature in R3. 相似文献
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We study surfaces M
2 in the four-dimensional affine space
equipped with its usual torsion-free connection D and parallel volume form given by the determinant. 相似文献
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Xiang-Dong Hou 《Designs, Codes and Cryptography》1997,12(1):75-82
We prove that the Reed-Muller code R(1,7) is normal. The normality of R(1,7) was a long-standing open question, and has an important consequence in a conjecture about the function t[n,k], the smallest covering radius of any [n,k] binary linear code. 相似文献
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It is proved that if M^n is an n-dimensional complete submanifold with parallel mean curvature vector and flat normal bundle in S^n+p(1), and if supM S 〈 α(n, H), where α(n,H)=n+n^3/2(n-1)H^2-n(n-2)/n(n-1)√n^2H^4+4(n-1)H^2,then M^n must be the totally urnbilical sphere S^n(1/√1+H^2).An example to show that the pinching constant α(n, H) appears optimal is given. 相似文献
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Philippe Castillon 《Annals of Global Analysis and Geometry》1999,17(6):563-579
In this work we determine the essential spectrum of the stability operator of a submanifold of the hyperbolic space with constant mean curvature h < 1 and finite total curvature. In some particular cases, we also give a bound on the number of eigenvalues which are below the essential spectrum. 相似文献
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多复变中正规权Zygmund空间上的几个性质 总被引:1,自引:0,他引:1
本文讨论了多复变中单位球上正规权Zygmund空间Z_μ(B)的一些性质.首先给出了Z_μ(B)函数的一种积分表示,接着证明了Z_μ(B)是正规权Bergman空间A_v~1(B)的对偶空间,其对偶对按如下形式给出:■,其中v(p)=(1-ρ~2)~(β+1)μ~(-1)(ρ)(0≤ρ<1)并且β>max{0,b-1}.最后作为积分表示和对偶的一个应用,作者给出了Z_μ(B)中每个函数的一个原子分解. 相似文献