局部Z-空间和Z-连续空间

对于一般广义子集系统Z,引入了局部Z-空间和Z-连续空间的概念,讨论了局部Z-空间的基本性质;基于收敛网,给出了局部Z-空间的等价刻画,证明了X为Z-连续空间当且仅当X为局部Z-空间。     

几乎概率度量空间(Ⅱ)

本文是作者文[1]的继续.该文中证明了 APM 空间的完备性与诱导一致结构的完备性等价;乘积 APM 空间是完备的当且仅当每个坐标空间是完备的;APM 空间是 m- 紧的当且仅当它是紧的;APM 空间的概率预紧性与诱导一致结构的预紧性等价;概率预紧的 APM 空间的诱导一致拓扑具有基数≤m 的基;m-紧的 APM 空间是 m-几乎可度量化;每个 t- 范数都连续的 APM 空间是可以完备扩张的。     

Rm上Banach-值函数的强McShane积分

在本文中,我们定义和研究了I0Rm到Banach空间X中函数的强McShane积分,直接证明了强Mcshane积分与Bochner积分是等价的,McShane积分与强Mcshane积分等价当且仅当Banach空间X有限维. 从而部分地回答了R.A.Gordon的一个公开问题.     

Dirichlet空间上一类乘法算子的酉等价类

本文研究了Dirichlet空间D上由二阶Blaschke积φ定义的乘法算子M_φ的酉等价类.主要结果表明对于D的一个乘子ψ,乘法算子M_ψ酉等价于M_φ当且仅当存在常数θ,|θ|θ=1,使得ψ(z)=φ(θz).这一结果是完全不同于Hardy空间与Bergman空间上的相应结果.     

广义函数Denjoy积分的收敛性问题

本文讨论广义函数De njoy积分的收敛性问题.首先给出了广义Denjoy可积函数空间中强收敛、弱收敛、弱~*收敛和广义函数Denjoy积分收敛的关系;证明拟一致收敛是广义函数Denjoy积分收敛的一个充分必要条件;最后指出了Denjoy可积广义函数列弱~*收敛与强收敛等价当且仅当原函数等度连续.     

WQN_*-空间与半连续函数(英文)

给出了WQN*-空间的一些刻画,证明了X是WQN*-空间当且仅当它有性质DSSP*,而且还证明了X具有性质DSSP*等价于X是S1(Γ,Γ)-空间.     

关于拟连续Domain的一个注记

证明了:(1)具有性质M的dcpo为拟连续domain当且仅当其上的下拓扑开集格在集合包含序下为连续格;(2)对于dcpo L,L为拟连续domain当且仅当ΣL的Hoare空间为局部强紧空间.     

半连续格上的半基和局部半基

在完备格上引入了半基和局部半基的概念,给出了半基和局部半基的性质及若干等价刻画,证明了一个完备格是半连续格当且仅当它具有半基也当且仅当它每点有局部半基。在此基础上定义了半连续格的权和特征,探讨了半连续格的权和特征与其上赋予半Scott拓扑和半Lawson拓扑时的拓扑空间的权和特征的关系。解决了文献[8](赵彬,刘妮.连续Domain的特征和浓度,陕西师范大学学报,2002,30(2):1~6)中提出的一个问题。     

关于局部紧空间的闭Lindel(o¨)f映象

本文给出了两类局部紧空间闭L(Lindelf)映象的内部特征,证明了空间X是仿紧局部紧空间的闭L映象当且仅当X是具有σ-局部有限k系的k′空间,由此得到在k′空间类中,仿紧局部紧空间的闭L映象等价于仿紧局部紧空间的商SL映象.同时还证明了空间X是局部紧度量空间的闭L映象当且仅当X是具有σ-局部有限紧k网的Fréchet空间.     

关于局部紧空间的闭Lindelf映象

本文给出了两类局部紧空间闭 L (Lindelof)映象的内部特征 ,证明了空间 X是仿紧局部紧空间的闭 L映象当且仅当 X是具有σ-局部有限 k系的 k′空间 ,由此得到在 k′空间类中 ,仿紧局部紧空间的闭 L映象等价于仿紧局部紧空间的商 SL映象 .同时还证明了空间 X是局部紧度量空间的闭 L映象当且仅当 X是具有σ-局部有限紧 k网的 Fréchet空间 .     

非自反Banach空间中的度量投影

该文给出非自反Banach空间中一类超平面上度量投影的表达式．在近严格凸Banach空间中,研究了它们的连续性．对于对偶Banach空间X*,给出弱*闭子集上度量投影的一些连续性结果．     

THE COMPLETENESS PROBLEM IN SPACES OF PETTIS INTEGRABLE FUNCTIONS

Abstract

Two subspaces of the space of Banach space valued Pettis integrable functions are considered: the space P(μ, X, var) of Pettis integrable functions with integrals of finite variation in a Banach space X and LLN(μ,X,var), the space of functions satisfying the law of large numbers. It is proved that LLN(μ,X*,var) is always complete and P(μ, X*,var) is complete if Martin's axiom and the perfectness of μ are assumed. Moreover, a non-trivial example of a non-conjugate Banach space X with non-complete P(μ, X, var) is presented.     

When Does the Equality J(X~*) = J(X) Hold for a Two-dimensional Banach Space X ?

In this paper, we consider the following problem about the James constant: When does the equality J(X*) = J(X) hold for a Banach space X ? It is known that the James constant of a Banach space does not coincide with that of its dual space in general. In fact, we already have counterexamples of two-dimensional normed spaces that are equipped with either symmetric or absolute norms. However,we show that if the norm on a two-dimensional space X is both symmetric and absolute, then the equality J(X*) = J(X) holds. This provides a global answer to the problem in the two-dimensional case.     

STRONGLY SEQUENTIALLY CONTINUOUS FUNCTIONS

Abstract

Given a topological abelian group G, we study the class of strongly sequentially continuous functions on G. Strong sequential continuity is a property intermediate between sequential continuity and uniform sequential continuity, which appeared naturally in the study of smooth functions on Banach spaces. In this paper, we shall mainly concentrate on the gap between strong sequential continuity and uniform sequential continuity. It turns out that if G has some completeness property—for example, if it is completely metrizable—then all strongly sequentially continuous functions on G are uniformly sequentially continuous. On the other hand, we exhibit a large and natural class of groups for which the two notions differ. This class is defined by a property reminiscent of the classical Dirichlet theorem; it includes all dense sugroups of R generated by an increasing sequence of Dirichlet sets, and groups of the form (X, w), where X is a separable Banach space failing the Schur property. Finally, we show that the family of bounded, real-valued strongly sequentially continuous functions on G is a closed subalgebra of l∞(G).     

ε-WEAKLY CHEBYSHEV SUBSPACES OF BANACH SPACES

We will define and characterize ε-weakly Chebyshev subspaces of Banach spaces. We will prove that all closed subspaces of a Banach space X are ε-weakly Chebyshev if and only if X is reflexive.     

Banach空间闭超平面上度量投影的连续性

该文给出Banach空间X的对偶空间X~*中闭超平面上度量投影的表达式,并在Banach空间中研究了闭超平面上度量投影的连续性.     

Certain classes of sets in Banach spaces and a topological characterization of operators of type RN

We study properties of bounded sets in Banach spaces, connected with the concept of equimeasurability introduced by A. Grothendieck. We introduce corresponding ideals of operators and find characterizations of them in terms of continuity of operators in certain topologies. The following result (Corollary 9) follows from the basic theorems: Let T be a continuous linear operator from a Banach space X to a Banach space Y. The following assertions are equivalent:

1. T is an operator of type RN;
2. for any Banach space Z, for any number p, p > 0, and any p-absolutely summing operator U:Z → X the operator TU is approximately p-Radonifying;
3. for any Banach space Z and any absolutely summing operator U:Z → X the operator TU is approximately 1-Radonifying.

We note that the implication I)?2), is apparently new even if the operator T is weakly compact.     

非线性Φ 伪压缩映象不动点的具误差的迭代过程

该文的目的是要引入比重要的 强伪压缩映象更一般的Φ 伪压缩映象，并且在更一般的假设下，用具误差的 Ishikawa和 Mann迭代过程去研究这类映象不动点的迭代逼近问题。研究结果表明：Φ 伪压缩映象T的一致连续性保证了在任意实Banach空间E中，Ishikawa迭代序列强收敛于T的唯一不动点；进一步，如果E是一致光滑的则T的连续性是不必要的     

Clarkson不等式与Banach空间几何

我们证明了Banach空间X是Clarkson p型（q余型）当且仅当X是一个特殊的p一致光滑空间（q-一致凸空间（）,我们还找到刻划型（余型）的一系列鞅不等式,同时,我们得到了均方函数sharp不等式。     

Controlled convergence theorems for Henstock-Kurzweil-Pettis integral on m-dimensional compact intervals

In this paper we use a generalized version of absolute continuity defined by J. Kurzweil, J. Jarník, Equiintegrability and controlled convergence of Perron-type integrable functions, Real Anal. Exch. 17 (1992), 110–139. By applying uniformly this generalized version of absolute continuity to the primitives of the Henstock-Kurzweil-Pettis integrable functions, we obtain controlled convergence theorems for the Henstock-Kurzweil-Pettis integral. First, we present a controlled convergence theorem for Henstock-Kurzweil-Pettis integral of functions defined on m-dimensional compact intervals of ℝ ^m and taking values in a Banach space. Then, we extend this theorem to complete locally convex topological vector spaces.