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1.
徐慧群 《数学研究》2006,39(2):151-154
讨论了从Finsler流形到Riemannian流形的稳定调和映照的不存在性,得到了一个拼挤定理.  相似文献   

2.
Browder[1]已得到了Schauder不动点定理的加强形式.许多作者从不同方向推广了Browder的结果.最近H.M.Ko;K.K.Tan[2]在放松紧性条件下得到了Browder定理的改进,K.K.Tan[3]将Browder定理推广到了集值映象对的重合定理,在本文中我们得到了集值映象对的某些重合定理,它们分别改进和推广了[1,2,3]中主要结果.  相似文献   

3.

The paper is devoted to finding conditions, sufficient for uniform local univalence of sense-preserving mappings, harmonic in the unit disc of the complex plane; the conditions are given in terms of the generalized Schwarzian derivative introduced by R. Hernández and M. J. Martín. The main section contains proofs of the conditions of univalence and uniform local univalence. In the proofs, the methods of the theory of linear-invariant families and generalized Schwarzian derivatives are used. The proved criteria are effective in the case of quasiconformal harmonic mappings; this is confirmed by examples. In the final section, some related methods are applied to harmonic mappings associated with non-parametric minimal surfaces. An estimation of the Gaussian curvature of minimal surfaces is obtained; it is given in the terms of the order of the associated harmonic mapping.

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4.
Some sharp estimates for coefficients, distortion and the growth order are obtained for harmonic mappings $f ∈ TL^α_H$which are locally univalent harmonic mappings in the unit disk $\mathbb{D}:=\{z:|z| < 1\}$. Moreover, denoting the subclass $TS^α_H$ of the normalized univalent harmonic mappings, we also estimate the growth of $|f|,$ $f ∈ TS^α_H,$ and their covering theorems.  相似文献   

5.
Some sharp estimates for coefficients, distortion and the growth order are obtained for harmonic mappings $f \in TL^{\alpha}_H,$ which are locally univalent harmonic mappings in the unit disk $\mathbb{D}:=\{z:|z|<1\}.$ Moreover, denoting the subclass $TS^{\alpha}_H$ of the normalized univalent harmonic mappings, we also estimate the growth of $|f|,$ $f \in TS^α_H,$ and their covering theorems.  相似文献   

6.
We show that several previously established convergence theorems for infinite products and powers of nonexpansive mappings continue to hold even when summable computational errors are present. Such results find application in methods for solving convex feasibility and optimization problems.  相似文献   

7.
In this article, some uniqueness theorems of meromorphic mappings in several complex variables sharing hyperplanes in general position are proved with truncated multiplicities.  相似文献   

8.
研究了单位开圆盘内保向复值的调和函数类,其中函数的解析部分满足一定的从属条件.完整的给出了该函数类Bloch常数的界、系数估计、增长和偏差不等式的界.进一步,通过指定一些关键参数,证明其pre-Schwarzian导数的范数也是有界的.  相似文献   

9.
F-调和映照的不存在性定理   总被引:2,自引:0,他引:2       下载免费PDF全文
本文主要讨论一类F-调和映照的不存在性问题,从而得到相应的Liouville型定理.  相似文献   

10.
Banach空间中渐近非扩张映象的收敛性定理   总被引:16,自引:0,他引:16  
张石生  徐裕光  何昌 《数学学报》2003,46(4):665-672
本文在Banach空间中引入和研究渐近非扩张映象及非扩张映象的某些类型的迭代序列的收敛性,其结果改进和推广了最新的一些结果,  相似文献   

11.
本文首次通过借助Kakutani-Fan-Glicksberg固定点定理和非线性标量化,研究了向量值映射的Benson锥鞍点定理.然后,通过使用该Kakutani-Fan-Glicksberg固定点定理,同样得到了集值映射的锥松鞍点定理.  相似文献   

12.
单叶调和映射   总被引:3,自引:0,他引:3  
张玉林 《数学进展》1993,22(5):402-410
由于在极小曲面理论中的作用,对调和映射的研究已有较长时间。1984年以来,经典解析单叶映射的理论被推广至调和单叶映射,并获得许多结论。这些工作引起人们对它的浓厚兴趣。该文介绍这一课题某些重要成果的概貌,并指出一些尚未解决的问题。它共分六个部分:映射定理;单叶调和函数的数值估计;特殊映射;变分方法;境界性质和在极小曲面中的应用。  相似文献   

13.
研究了完备度量空间中集值映象序列的不动点性质,得到了几个新的不动点定理,并指出了参考文献中的一个错误.  相似文献   

14.
张顺燕  宫贵福 《数学进展》1995,24(6):550-555
本文从几何函数论的观点研究了一类复值调和典则实函数,在某些假定之下形成了类T_H和它的子类T ̄0_H,并给出了T_H和T ̄0_H的闭凸壳HT_H和HT ̄0_H文中证明了T_H是正规的,T ̄0_H是紧的。T ̄0_H与HT ̄0_H中的函数可用积分公式表示。  相似文献   

15.
CWC映射和度量化定理   总被引:1,自引:0,他引:1  
燕鹏飞  林寿 《数学进展》2007,36(2):153-158
利用CWC映射,本文获得了对称度量空间和g可度量空间的特征,建立了几个度量化定理,改进了一些已知结果.主要的定理是证明正则空间X是可度量化空间当且仅当存在X上的CWC映射g满足如下条件: (Ⅰ)若序列{xn}和{yn}对于每一n∈N有xn∈g(n,yn)且xn→x,则yn→x.(Ⅱ)若序列{xn}和{yn}对于每一n∈N有yn∈g(n,yn)且xn→x,则yn→x.  相似文献   

16.
Minimax Theorems for Set-Valued Mappings   总被引:1,自引:0,他引:1  
In this paper, we deal with two types of minimax theorems for set-valued mappings and vector-valued functions.  相似文献   

17.
Set-Valued and Variational Analysis - For a Hilbert space X and a mapping $F: X\rightrightarrows X$ (potentially set-valued) that is maximal monotone locally around a pair $(\bar {x},\bar {y})$ in...  相似文献   

18.
The existence of a zero for a holomorphic functions on a ball or on a rectangle under some sign conditions on the boundary generalizing Bolzano's ones for real functions on an interval is deduced in a very simple way from Cauchy's theorem for holomorphic functions.A more complicated proof,using Cauchy's argument principle,provides uniqueness of the zero,when the sign conditions on the boundary are strict.Applications are given to corresponding Brouwer fixed point theorems for holomorphic functions.Extensions to holomorphic mappings from Cn to Cn are obtained using Brouwer degree.  相似文献   

19.
Weak Convergence Theorems for Nonexpansive Mappings and Monotone Mappings   总被引:18,自引:0,他引:18  
In this paper, we introduce an iteration process of finding a common element of the set of fixed points of a nonexpansive mapping and the set of solutions of a variational inequality problem for an inverse strongly-monotone mapping, and then obtain a weak convergence theorem. Using this result, we obtain a weak convergence theorem for a pair of a nonexpansive mapping and a strictly pseudocontractive mapping. Further, we consider the problem of finding a common element of the set of fixed points of a nonexpansive mapping and the set of zeros of an inverse strongly-monotone mapping.  相似文献   

20.
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