LF拓扑空间中的Urysohn闭性

在LF拓扑空间中引入Urysohn闭性、Urysohnα-远域族等概念．利用分子网、滤子及理想的μ-收敛性概念研究Urysohn闭性的特征．证明了Urysohn闭性关于μ-闭集是遗传的，Urysohn闭性是弱拓扑不变性质等结果．同时，利用Urysohnα-远城族、Urysohnr-覆盖及闭图等概念给出Urysohn闭性的几何刻画．     

格上点式一致结构的刻划与点式度量化定理

本文通过对格上远域映射,特别是△-映射和＊-映射的性质的研究,给出了格上点式一致结构的若干简明刻划,证明了几个重要的格上点式度量化定理,并提出了与格上点式度量理论相协调的若干分离性公理.     

经典公理集合论系统与中介公理集合论系统之间的包含关系

本文首先在中介公理集合论系统ＭＳ中构造出Ｐｅａｎｏ自然数系统，以此为基础重新定义了ＭＳ中的良集概念，证明了新定义的良集满足经典公理集合论系统ＺＦＣ^－（ＺＦＣ中去掉正则公理的集合论系统）的全部公理，从而说明经典公理集合论系统ＺＦＣ^－为中介公理集合论系统ＭＳ的子系统．     

拓扑分子格的PS-T*分离公理

利用准半开邻域引入了拓扑分子格的一类新的PS-Ti*分离公理(i=0,1,2,3,4),给出了这些分离性的刻画,得到了这些分离性是PS-同胚序同态下保持不变的性质。     

引理与弧连通完全分配格

称一个完全分配格L满足Urysohn条件,如果对任一正规空间X及X的任意两个不交闭子集A,B都有连续映射fX→L,使得f［A］=0,f［B］=1,这里L赋予区间拓扑.本文证明了完全分配格L满足Urysohn条件当且仅当L弧连通,而L弧连通又等价于L有同构于单位区间I的极大链     

数学归纳法与匹亚诺公理

数学归纳法推理是典型的三段论，而不是完全归纳法，其基础是自然数列的性质，而不是逻辑公理，皮亚诺公理中的归纳法公理并不是一种证明方法，而是自然数集的一条不可缺少的根据性质。     

基于滤子收敛的分离公理的等价刻画

在拓扑空间中,滤子是用来描述收敛的主要工具之一,也是用来研究收敛空间的主要工具。本文对拓扑空间中的滤子,定义了三个新的滤子■,*和△,并用它们刻画了拓扑空间中的T0,T1,T2,正则,完全正则和正规等分离性。     

合作博弈的比例分离解及其在区域经济一体化中的应用

文章对合作博弈理论进行了研究,结合比例分配以及联盟形成过程,提出了比例分离解的概念.该解首先利用给定权重,基于回报率递减划分大联盟,得到了大联盟的适配划分,随后由适配划分确定的加入顺序对划分联盟的边际贡献按比例分配.然后,基于最高回报一致性对比例分离解的公理刻画进行了研究,得到了3个刻画定理.最后,将新的解概念应用到区域经济一体化问题中,建立了经济协同博弈模型,并以长三角地区为例,分析了该区域经济协同发展的贡献情况和发展规划.     

聚合公理系统的布尔值模型

本文以ＺＦｃ聚合公理系统为基础，构造了ＺＦｃ的布尔值模型，证明了关键定理９、定理１５，使得ＺＦ集合公理系统的布尔值模型ＶＯｎ＾（Ｂ）是聚合公理系统的布尔值模型〔ＶＯＮ＾（Ｂ）〕的子模型，并且ＺＦ集合公理组在〔ＶＯＮ＾（Ｂ）〕中满足。     

公理A自同态的统计性结果（英文）

本文对公理A自同态建立了中心极限定理和大偏差估计，并且复习了已知的有关统计性结果。     

More on continuously Urysohn spaces

We study the properties of weakly continuously Urysohn and continuously Urysohn spaces. We show that being a (weakly) continuously Urysohn space is not a multiplicative property, and that this property is not preserved under perfect maps. However, being a weakly continuously Urysohn space is preserved under perfect open maps. By using the scattering process, we show that the class of protometrizable spaces is also contained in the class of continuously Urysohn space. We also give a characterization of the continuously Urysohn property for well-ordered spaces, and prove that a paracompact locally continuously Urysohn ordered space is continuously Urysohn.     

Pretopologies, preuniformities and probabilistic metric spaces

Summary A pretopology on a given set can be generated from a filter of reflexive relations on that set (we call such a structure a preuniformity). We show that the familly of filters inducing a given pretopology on Xform a complete lattice in the lattice of filters on X. The smallest and largest elements of that lattice are explicitly given. The largest element is characterized by a condition which is formally equivalent to a property introduced by Knaster--Kuratowski--Mazurkiewicz in their well known proof of Brouwer's fixed point theorem. Menger spaces and probabilistic metric spaces also generate pretopologies. Semi-uniformities and pretopologies associated to a possibly nonseparated Menger space are completely characterized.     

Extensible hyperplane nets

Extensible (polynomial) lattice point sets have the property that the number N of points in the node set of a quasi-Monte Carlo algorithm may be increased while retaining the existing points. Explicit constructions for extensible (polynomial) lattice point sets have been presented recently by Niederreiter and Pillichshammer. It is the aim of this paper to establish extensibility for a powerful generalization of polynomial lattice point sets, the so-called hyperplane nets.     

Weakly continuously Urysohn spaces

We study weakly continuously Urysohn spaces, which were introduced in [P.L. Zenor, Continuously extending partial functions, Proc. Amer. Math. Soc. 135 (1) (2007) 305-312]. We show that every weakly continuously Urysohn wΔ-space has a base of countable order, that separable weakly continuously Urysohn spaces are submetrizable, hence continuously Urysohn, that monotonically normal weakly continuously Urysohn spaces are hereditarily paracompact, and that no linear extension of any uncountable subspace of the Sorgenfrey line is weakly continuously Urysohn. These results generalize various results in the literature concerning continuously Urysohn spaces.     

Σ-Groups as Convergence Groups

A Σ-group is an abelian group in which certain infinite sums are postulated to exist and to satisfy axioms suggested by the properties of unconditional sums in abelian convergence groups. Two notions of convergence are considered: in terms of nets, and in terms of filters. It is proved that every Σ-group can be regarded as a net convergence group (of a particular type). An example is given to show that the same does not remain true if filters are used instead of nets. For the special class of ‘adic’ Σ-groups, however, it is proved that filters are adequate.     

On fuzzy fantastic filters of lattice implication algebras

Fuzzification of a fantastic filter in a lattice implication algebra is considered. Relations among a fuzzy filter, a fuzzy fantastic filter, and fuzzy positive implicative filter are stated. Conditions for a fuzzy filter to be a fuzzy fantastic filter are given. Using the notion of level set, a characterization of a fuzzy fantastic filter is considered. Extension property for fuzzy fantastic filters is established. The notion of normal/maximal fuzzy fantastic filters and complete fuzzy fantastic filters is introduced, and some related properties are investigated.     

Extended topology: Filters and convergence I

Conclusion The above-mentioned results show some of the advantages of using extended filters. It has already been shown that the family of all proper extended filters forms a complete lattice. Many of the results obtained by using Cartan's filters can be obtained by using proper extended filters; it is not necessary to impose the condition that they should be closed with respect to finite intersections. And for most purposes it is sufficient if extended filters have the pair-wise intersection property; for instance limits are unique under this condition.In the next paper I propose to take up the question of convergence. Convergence will be dealt with in a setting more general than a topology of which convergence is extended topologies and topologies will be special cases. Wherever convenient relation theory will be used in dealing with extended topology which generalizes extended topology defined in terms of expansive functions.This research was supported by the National Science Foundation Research Participation Program in Mathematics at the University of Oklahoma, Norman, Oklahoma.     

Filters in (Quasiordered) Semigroups and Lattices of Filters

A filter in a semigroup is a subsemigroup whose complement is an ideal. (Alternatively, in a quasiordered semigroup, a slightly more general definition can be given.) We prove a number of results related to filters in a semigroup and the lattice of filters of a semigroup. For instance, we prove that every complete algebraic lattice can be the lattice of filters of a semigroup. We prove that every finite semigroup is a homomorphic image of a finite semigroup whose lattice of filters is boolean and which belongs to the pseudovariety generated by the original semigroup. We describe filter lattices of some well-known semigroups such as full transformation semigroups of finite sets (which are three-element chains) and free semigroups (which are boolean).     

On the geometry of Urysohn's universal metric space

In recent years, much interest was devoted to the Urysohn space U and its isometry group; this paper is a contribution to this field of research. We mostly concern ourselves with the properties of isometries of U, showing for instance that any Polish metric space is isometric to the set of fixed points of some isometry φ. We conclude the paper by studying a question of Urysohn, proving that compact homogeneity is the strongest homogeneity property possible in U.