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排序方式: 共有2439条查询结果,搜索用时 15 毫秒
21.
The present paper deals with the long-time behavior of a class of nonautonomous retarded semilinear parabolic differential equations. When the time delays are small enough and the spectral gap conditions hold, the inertial manifolds of the nonautonomous retard parabolic equations are constructed by using the Lyapunov-Perron method. 相似文献
22.
Xu Cheng 《Geometriae Dedicata》2002,90(1):115-125
In this paper, we consider the coisotropic submanifolds in a Kähler manifold of nonnegative holomorphic curvature. We prove an intersection theorem for compact totally geodesic coisotropic submanifolds and discuss some topological obstructions for the existence of such submanifolds. Our results apply to Lagrangian submanifolds and real hypersurfaces since the class of coisotropic submanifolds includes them. As an application, we give a fixed-point theorem for compact Kähler manifolds with positive holomorphic curvature. Also, our results can be further extended to nearly Kähler manifolds. 相似文献
23.
Summary At first, a necessary and sufficient condition for a K?hler-Norden manifold to be holomorphic Einstein is found. Next, it
is shown that the so-called (real) generalized Einstein conditions for K?hler-Norden manifolds are not essential since the
scalarcurvature of such manifolds is constant. In this context, we study generalized holomorphic Einstein conditions. Using
the one-to-one correspondence between K?hler-Norden structures and holomorphic Riemannian metrics, we establish necessary
and sufficient conditions for K?hler-Norden manifolds to satisfy the generalized holomorphic Einstein conditions. And a class
of new examples of such manifolds is presented. Finally, in virtue of the obtained results, we mention that Theorems 1 and
2 of H. Kim and J. Kim [10] are not true in general. 相似文献
24.
Th. Friedrich I. Kath A. Moroianu U. Semmelmann 《Journal of Geometry and Physics》1997,23(3-4):259-286
A nearly parallel G2-structure on a seven-dimensional Riemannian manifold is equivalent to a spin structure with a Killing spinor. We prove general results about the automorphism group of such structures and we construct new examples. We classify all nearly parallel G2-manifolds with large symmetry group and in particular all homogeneous nearly parallel G2-structures. 相似文献
25.
扰动周期KdV方程的小波基分析 总被引:2,自引:2,他引:0
本文利用样条小波基构造近似惯性流形来研究扰动周期KdV方程的长期动力学行为· 相似文献
26.
Xianzhe Dai 《Advances in Mathematics》2007,214(2):551-570
We prove a Hitchin-Thorpe inequality for noncompact Einstein 4-manifolds with specified asymptotic geometry at infinity. The asymptotic geometry at infinity is either a cusp bundle over a compact space (the fibered cusps) or a fiber bundle over a cone with a compact fiber (the fibered boundary). Many noncompact Einstein manifolds come with such a geometry at infinity. 相似文献
27.
The object of the present paper is to study quasi-conformally flat weakly Ricci symmetric manifolds.
相似文献
28.
谱约束下对称正交对称矩阵束的最佳逼近 总被引:3,自引:0,他引:3
讨论了对称正交对称矩阵的广义逆特征值问题,得到了通解表达式和最佳解的表达式。 相似文献
29.
W. Schindler 《Computational Geometry》1994,4(6):327-343
Stochastic simulations on manifolds usually are traced back to
n via charts. If a group G is acting on a manifold M and if the respective distribution v is invariant under this group action then in many cases of practical interest there exists a more convenient approach which uses equivariant mappings. The concept of equivariant mappings will be discussed intensively at the instance of the Grassman manifold in which case G equals the orthogonal group. Further advantages of this concept will be demonstrated by applying it to a probabilistic problem from the field of combinatorial geometry. 相似文献
30.
张宗劳 《南昌大学学报(理科版)》2004,28(3):208-209
借助于Hessian比较定理和上下解方法,证明了对于相当多的一类非负函数f,负曲率完备黎曼流形上的方程△u=f都存在有界的整体解,从而刻画了这些黎曼流形的双曲性程度。 相似文献