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1.
切片与Banach空间的凸性,光滑性   总被引:14,自引:1,他引:13  
方习年  王建华 《数学杂志》1999,19(3):293-298
本文用单位球的切片统一且简捷地处理Banach空间的(局部)K一致凸、近一致凸、近一致光滑性;定义Banach空间的(局部)K一致光滑、局部近一致凸、局部近一致光滑、近-强凸、近-强光滑性等概念,并讨论上述凸性,光滑性的关系及性能。  相似文献   

2.
Bekj.  TN 《数学杂志》1999,19(1):34-38
本文研究了解析一致凸性Banach空间,证明了重赋范定理并且给出了具有解析一致凸性的一些具体空间。  相似文献   

3.
Banach空间中渐近正则的Lipschitz半群的不动点定理   总被引:1,自引:0,他引:1  
本文首先定义了渐近正则的Lipschitz半群的概念.其次,证明了p一致凸Banach空间中渐近正则的Lipschitz半群的不动点定理.同时也证明了具有正规结构系数的一致凸Eanach空间中的渐近正则的Lipschitz半群的一个新的不动点定理.  相似文献   

4.
Banach空间的接近光滑性,接近凸性和滴性及其应用   总被引:6,自引:2,他引:4  
曹温淳 《数学杂志》1995,15(2):187-191
本文发现,用在一定条件下序列的相对列紧性可以统一而且十分简捷地处理Banach空间的局部接近一致光滑性,弱Hahn-Banach光滑性及滴性等概念。并由此推出了它们之间的一些新关系,得出一些新性质,也得到了Banach空间自反的一些新等价条件,在讨论了接近一致光滑和接近一致凸之间的关系的基础上,我们还得到了Bochner空间的相应一些性质。  相似文献   

5.
本文给出p一致凸和q一致光滑的Banach空间中,距离投影的Lipschitz常数的全局估计.  相似文献   

6.
本文首先通过暴露集和暴露泛函的概念引入了闭凸集的紧-严格凸、紧-强凸、紧-一致凸及紧-非常凸等概念。并用对偶映射给出了Banach空间的两种新光滑性—紧-一致光滑与紧-非常光滑。然后特别研究了Banach空间的紧-非常凸与紧-非常光滑。此外还得到关于对偶映射的两个新结果。  相似文献   

7.
洪毅  林运泳 《数学学报》1995,38(6):837-844
本文研究了一类Banach空间上凸映射的性质。找出了一类Banach空间上单位球上凸映射的特征,并利用这些结果研究了一类有界凸域上的所有凸映射.  相似文献   

8.
紧—凸性与紧—光滑性   总被引:3,自引:0,他引:3  
郑喜印 《数学进展》1995,24(4):342-347
本文首先通过暴露集和暴露泛函的概念引入卫闭凸集的紧-严格凸、紧-强凸、紧-一致凸及紧-非常凸等概念。用对偶映射给出了Banach空间的两种新光滑性-紧-一致光滑与紧-非常光滑。然后特别研究了Banach空间的紧-非常凸与紧-非常光滑。此外还得到关于对偶映射的两个新结果。  相似文献   

9.
q均方函数的增长速度与Banach空间的一致凸性   总被引:1,自引:1,他引:0  
在比短文中我们研究了Banach空间值鞅的q均方函数的增长速度并用以刻划值空间的一致凸性.  相似文献   

10.
甘师信 《数学杂志》1994,14(3):387-395
本文证明了Banach空间值鞅的一些不等式,讨论了Banach空间的凸性及光滑性与某些鞅不等的式的联系,给出了Hilbert空间的一个鞅不等式刻划,同时还讨论了一致P光滑空间中鞅的弱大数定律,本文的结论推广与改进了很多熟知的定理。  相似文献   

11.
This paper through discussing subdifferentiability and convexity of convex functions shows that a Banach space admits an equivalent uniformly [locally uniformly, strictly] convex norm if and only if there exists a continuous uniformly [locally uniformly, strictly] convex function on some nonempty open convex subset of the space and presents some characterizations of super-reflexive Banach spaces. Supported by NSFC  相似文献   

12.
We study the support and convergence conditions for a metric space to be coarsely embeddable into a uniformly convex Banach space. By using ultraproducts we also show that the coarse embeddability of a metric space into a uniformly convex Banach space is determined by its finite subspaces.  相似文献   

13.
In this paper, we introduce a new two-step iterative scheme for two asymptotically nonexpansive nonself-mappings in a uniformly convex Banach space. Weak and strong convergence theorems are established for the new two-step iterative scheme in a uniformly convex Banach space.  相似文献   

14.
Using the concept of asymptotic center we obtain the existence of fixed points having preassigned location for a wider class of asymptotic nonexpansive mappings in a uniformly convex Banach space. This generalization leads us to get a recent result of Alfuraidan and Khamsi for continuous monotone asymptotic nonexpansive mappings as well as the classical fixed-point result of Geobel and Kirk for asymptotic nonexpansive mappings in a uniformly convex Banach space. Also we prove a fixed-point theorem for order preserving continuous maps on a quasiordered closed convex subset of a uniformly convex Banach sapce having monotone norm.  相似文献   

15.
We prove a new inequality valid in any two-dimensional normed space. As an application, it is shown that the identity mapping on the unit ball of an infinite-dimensional uniformly convex Banach space is the mean of n uniformly continuous retractions from the unit ball onto the unit sphere, for every n?3. This last result allows us to study the extremal structure of uniformly continuous function spaces valued in an infinite-dimensional uniformly convex Banach space.  相似文献   

16.
In this paper we show that a countable, residually amenable group admits a proper isometric affine action on some uniformly convex Banach space if and only if one (or equivalently, all) of its box families admits a fibred cofinitely-coarse embedding into some uniformly convex Banach space.  相似文献   

17.
It is shown that a Banach space with locally uniformly convex dual admits an equivalent norm that is itself locally uniformly convex.  相似文献   

18.
Almost transitive superreflexive Banach spaces have been considered in [C. Finet, Uniform convexity properties of norms on superreflexive Banach spaces, Israel J. Math. 53 (1986) 81–92], where it is shown that they are uniformly convex and uniformly smooth. We characterize such spaces as those convex transitive Banach spaces satisfying conditions much weaker than that of uniform convexity (for example, that of having a weakly locally uniformly rotund point). We note that, in general, the property of convex transitivity for a Banach space is weaker than that of almost transitivity.  相似文献   

19.
The goal of this article is to study the relations among monotonicity properties of real Banach lattices and the corresponding convexity properties in the complex Banach lattices. We introduce the moduli of monotonicity of Banach lattices. We show that a Banach lattice E is uniformly monotone if and only if its complexification EC is uniformly complex convex. We also prove that a uniformly monotone Banach lattice has finite cotype. In particular, we show that a Banach lattice is of cotype q for some 2?q<∞ if and only if there is an equivalent lattice norm under which it is uniformly monotone and its complexification is q-uniformly PL-convex. We also show that a real Köthe function space E is strictly (respectively uniformly) monotone and a complex Banach space X is strictly (respectively uniformly) complex convex if and only if Köthe-Bochner function space E(X) is strictly (respectively uniformly) complex convex.  相似文献   

20.
The main result is that a separable Banach space with the weak* unconditional tree property is isomorphic to a subspace as well as a quotient of a Banach space with a shrinking unconditional basis. A consequence of this is that a Banach space is isomorphic to a subspace of a space with a shrinking unconditional basis if and only if it is isomorphic to a quotient of a space with a shrinking unconditional basis, which solves a problem dating to the 1970s. The proof of the main result also yields that a uniformly convex space with the unconditional tree property is isomorphic to a subspace as well as a quotient of a uniformly convex space with an unconditional finite dimensional decomposition.  相似文献   

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