首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6篇
  国内免费   1篇
  完全免费   4篇
  数学   11篇
  2017年   2篇
  2016年   1篇
  2015年   1篇
  2014年   1篇
  2011年   1篇
  2009年   1篇
  2008年   2篇
  2007年   1篇
  2001年   1篇
排序方式: 共有11条查询结果,搜索用时 78 毫秒
1.
Complete space-like hypersurfaces with constant scalar curvature   总被引:6,自引:0,他引:6  
Let M n be a complete space-like hypersurface with constant normalized scalar curvature R in the de Sitter space S n + 1 1 and denote . We prove that if the norm square of the second fundamental form of M n satisfies , then either and M n is a totally umbilical hypersurface; or , and, up to rigid motion, M n is a hyperbolic cylinder . Received: 8 February 2001 / Revised version: 27 April 2001  相似文献
2.
In this paper, we give a weak classification of locally linear pseudofree actions of the cyclic group of order on a surface, and prove the existence of such an action which cannot be realized as a smooth action on the standard smooth surface.

  相似文献

3.
In this paper, the authors study the homologically trivial symplectic group actions on homotopy elliptic surfaces E(n) and get some rigidity results.  相似文献
4.
5.
Let X be a closed, simply-connected, smooth, spin 4-manifold whose intersection form is isomorphic to n( − E 8) ⊕ mH, where H is the hyperbolic form. In this paper, we prove that for n such that n ≡ 2  mod  4, there exists a locally linear pseudofree ℤ2-action on X which is nonsmoothable with respect to any possible smooth structure on X.  相似文献
6.
In this paper, we investigate the complete spacelike hypersurfaces with constant mean curvature and two distinct principal curvatures in an anti-de Sitter space. We give a characterization of hyperbolic cylinder and prove the conjecture in a paper by L. F. Cao and G. X. Wei [J. Math. Anal. Appl., 2007, 329(1): 408–414].  相似文献
7.
本文利用广义的Omori-Yau极大值原则,得到了广义的Robertson-Walker(GRW)时空中具有常高阶平均曲率并且边界包含在一slice中的类空超曲面的高度估计.同时利用这些结果得到了一些拓扑方面的结论.最后对拉普拉斯算子和一些椭圆型的微分算子利用Omori-Yau极大值原则,得到了一些更广泛的非存在性的结果.  相似文献
8.
我们研究的是浸入在半黎曼卷积空间$\epsilon\textit{I}\times _{f}M^{n}$的完备超曲面,其中$M^{n}$是连通的$n$维可定向黎曼流形.当纤维$M^{n}$是完备的,并且界面曲率$-k\leq K_{M}$, 其中$k$为正常数,对于高度函数$h$,如果对其梯度的范数进行适当限制,我们得到浸入在半黎曼卷积空间的完备超曲面是切片.我们运用的原理是是著名的推广的极大值原理.  相似文献
9.
Let X be a closed smooth 4-manifold which is homotopy equivalent to S 2 × S 2. In this paper we use Seiberg-Witten theory to prove that if X admits a spin symmetric group S 4 action of even type with b 2 + (X/S 4) = b 2 + (X), then as an element of R (S 4), Ind S4 D X = k 1 (1 − θ) + k 21 − ψ2) for some integers k 1 and k 2, where 1, θ, ψ1, ψ2 are irreducible characters of S 4 of degree 1, 1, 3, and 3 respectively. Authors’ address: Ximin Liu and Hongxia Li, Department of Applied Mathematics, Dalian University of Technology, Dalian 116024, P.R. China  相似文献
10.
Let G be a cyclic group of order 3, 5 or 7, and X=E(n) be the relatively minimal elliptic surface with rational base. In this paper, we prove that under certain conditions on n, there exists a locally linear G-action on X which is nonsmoothable with respect to infinitely many smooth structures on X. This extends the main result of [X. Liu, N. Nakamura, Pseudofree Z/3-actions on K3 surfaces, Proc. Amer. Math. Soc. 135 (3) (2007) 903-910].  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