函数空间不变余度量性质的一个推广

本文对函数空间在集开拓扑下的不变余度量性质进行了推广,给出了函数空间在紧开拓扑和点收敛拓扑下不变余度量化的充要条件．     

关于统计序列紧空间

在一般拓扑空间中,引入了序列紧空间的统计定义并讨论其相应的拓扑性质,深化了拓扑群与可度量化空间中关于序列紧空间的一些结果.     

csf可数空间的注记

讨论csf可数空间的性质,把csf可数空间刻画为度量空间的映像,同时探讨了伪紧的csf可数空间的第一可数性质,推广了Arhangel’skiˇ?关于度量空间伪开s映像的结果,证明了正则伪紧的仿拓扑群是可度量化的当且仅当它是csf可数的Fr′echet空间.     

概率度量空间的基本理论及应用(Ⅰ)*

本文系统地研究概率度量空间的基本理论和应用,讨论了概率度量空间的拓扑结构和性质;给出了概率度量空间,Menger概率度量空间以及概率线性赋范空间可度量化的条件及其度量函数的形式:得出了概率度量空间集合的各种概率有界性的表征等.作为这些结果的应用,我们讨论了概率线性赋范空间中线性算子的理论及概率度量空间中不动点的存在性问题.     

模糊拓扑空间两组度量公理的等价性及度量化

证明了在Fts中邓自克和胡诚明分别定义的度量公理,在相同的定义域P0上是等价的.由此,按邓自克定义的度量公理,我们获得了模糊拓扑空间可度量化的一个充分条件若(X,δ)是模糊T3且具有δ-Fuzzy,则它是一个可Fuzzy度量化空间.这是对邓自克文献[8]中度量化的结果的改进.     

函数空间上的Cauchy收敛拓扑(英文)

本文研究了度量空间X到实直线R上的连续函数空间C(X,R)上的Cauchy收敛拓扑Tc.u,点态收敛拓扑Tp.u,紧开拓扑Tk和一致收敛拓扑Tu相等的等价条件.利用Cauchy覆盖得到了(C(X,R),Tc.u)的特征与X的Cauchy覆盖数相等的一个对偶定理,获得了(C(X,R),Tc.u)可度量化当且仅当(C(X,R),Tc.u)是第一可数的当且仅当X具有可数Cauchy覆盖数,肯定地回答了Michael H Clapp等在文献[1]中提到的问题.     

可度量化拓扑向量空间中的不动点定理

本文在可度量化拓扑向量空间中建立了一个新的不动点定理 ,它部分推广了著名的 Tychonoff不动点定理 .     

关于紧覆盖π映射

本文利用紧有限分解覆盖的概念，给出了度量空间的紧覆盖π象以刻划，并证明了g可度量化空间是度量空间的紧覆盖紧映象．     

超空间与原空间动力系统之间的关系

设(X,d,f)为拓扑动力系统,其中X为局部紧可分的可度量化空间,d为紧型度量,f为完备映射,用2X表示由X的所有非空闭子集构成的集族,(2X,ρ,2f)为由(X,d,f)所诱导的赋予hit-or-miss拓扑的超空间动力系统.本文引入了余紧点传递和弱拓扑传递的定义.特别的,在X满足一定的条件时,给出了点传递,弱拓扑传递和余紧点传递之间的关系,并研究了(X,d,f)的余紧传递点,回复点和几乎周期点分别与(2X,ρ,2f)的传递点,回复点和几乎周期点之间的蕴含关系.这些结论丰富了赋予hit-or-miss拓扑的超空间的研究内容.     

概率度量空间的等距度量化

本文给出了概率度量空间等距同构于度量空间及一类伪度量族生成空间的充要条件;给出了概率赋范空间等距同构于赋范空间、赋B₀型准范空间及可赋准范空间的充要条件。     

Characterization of locally convex solid topologies of lebesgue on the vector latticeC(X)

We give some sufficient and necessary conditions such that the vector lattice of continuous functions on a compact topological space, not necessary metrizable, admits a locally convex and solid topology which is Lebesgue.

     

On Metric Boundedness Structures

Many years ago, S.-T. Hu gave necessary and sufficient conditions for a family of subsets of a metrizable space X to be the family of bounded sets for some admissible metric for the space. In this article, we show that in any noncompact metrizable space there are uncountably many distinct metric boundedness structures. Also, given an initial metric d for X, we look carefully at the problem of characterizing those boundedness structures determined by metrics uniformly equivalent to d. Applications to hyperspaces are given. Throughout, we rely on a dual approach to the study of metric boundedness.     

关于模糊拓扑环的模糊度量化

本文引入了模糊拓扑环可广义模糊度量化 ,可模糊伪度量化及可模糊度量化三个概念 ;并分别得到了模糊拓扑环可广义模糊度量化 ,可模糊伪度量化及可模糊度量化的三个充分必要条件     

Metric spaces and the axiom of choice

We study conditions for a topological space to be metrizable, properties of metrizable spaces, and the role the axiom of choice plays in these matters.     

On an equivalence of topological vector space valued cone metric spaces and metric spaces

Scalarization method is an important tool in the study of vector optimization as corresponding solutions of vector optimization problems can be found by solving scalar optimization problems. Recently this has been applied by Du (2010) [14] to investigate the equivalence of vectorial versions of fixed point theorems of contractive mappings in generalized cone metric spaces and scalar versions of fixed point theorems in general metric spaces in usual sense. In this paper, we find out that the topology induced by topological vector space valued cone metric coincides with the topology induced by the metric obtained via a nonlinear scalarization function, i.e any topological vector space valued cone metric space is metrizable, prove a completion theorem, and also obtain some more results in topological vector space valued cone normed spaces.     

When is a lots densely orderable?

We obtain sufficient conditions for a linearly ordered topological space (LOTS) to be densely orderable. As a consequence we obtain a characterization of those metrizable LOTS with connected ordered compactifications.     

Topological vector spaces, compacta, and unions of subspaces

In the first two sections, we study when a σ-compact space can be covered by a point-finite family of compacta. The main result in this direction concerns topological vector spaces. Theorem 2.4 implies that if such a space L admits a countable point-finite cover by compacta, then L has a countable network. It follows that if f is a continuous mapping of a σ-compact locally compact space X onto a topological vector space L, and fibers of f are compact, then L is a σ-compact space with a countable network (Theorem 2.10). Therefore, certain σ-compact topological vector spaces do not have a stronger σ-compact locally compact topology.In the last, third section, we establish a result going in the orthogonal direction: if a compact Hausdorff space X is the union of two subspaces which are homeomorphic to topological vector spaces, then X is metrizable (Corollary 3.2).     

Spaces of Densely Continuous Forms

The set C(X,Y) of continuous functions from a topological space X into a topological space Y is extended to the set D(X,Y) of densely continuous forms from X to Y, such form being a kind of multifunction from X to Y. The topologies of pointwise convergence, uniform convergence, and uniform convergence on compact sets are defined for D(X,Y), for locally compact spaces X and metric spaces Y having a metric satisfying the Heine–Borel property. Under these assumptions, D(X,Y) with the uniform topology is shown to be completely metrizable. In addition, if X is compact, D(X,Y) is completely metrizable under the topology of uniform convergence on compact sets. For this latter topology, an Ascoli theorem is established giving necessary and sufficient conditions for a subset of D(X,Y) to be compact.     

Completeness results in probabilistic metric spaces

In this paper, we consider complete probabilistic metrizable (topological) space and prove that any G_δ set in a complete probabilistic metric spaces is a topologically complete probabilistic metrizable space.