关于连续偏序集的一个刻画定理(英文)

本文给出了连续偏序集的一个刻画定理及相应的代数偏序集刻画定理.进一步得出连续偏序集P关于其Scott拓扑是局部紧的,而且OFilt(P)是一个domain.这推广了关于dcpo的对应结果.     

测度拓扑和连续偏序集的刻画

研究偏序集上的测度拓扑以及与其它内蕴拓扑间的关系,利用测度拓扑刻画了偏序集的连续性.构造了反例说明存在完全分配格,其上的测度拓扑不是连续格从而不是局部紧拓扑.     

［X→L］上的Isbell拓扑和Scott拓扑

本文证明了：对ｃｏｒｅｃｏｍｐａｃｔ空间Ｘ和具有最小元的有界完备连续ＤＣＰＯＬ，［Ｘ→Ｌ］上的Ｉｓｂｅｌｌ拓扑与Ｓｃｏｔｔ拓扑重合．并且构造两个反例说明：若Ｌ不具有最小元，或Ｌ具有最小元但不满足有界完备性，则［Ｘ→Ｌ］上的Ｉｓｂｅｌｌ拓扑与Ｓｃｏｔｔ拓扑不必重合．     

连续Domain的遗传性及其不变性

引入Domain子空间的概念,得到Scott开集和闭集都是Domain的子空间。证明连续Domain或代数Domain对开子空间和闭子空间都是可遗传的。证明连续Domain或代数Domain在保Waybelow序的Scott连续映射下保持不变。     

关于连续Domain权的进一步结果

在连续格理论的基础上探索连续Domain的权与相应Scott拓扑空间的权之间的关系,并进一步讨论其与相应的Lawson拓扑空间的权之间的关系,最后给出在连续Domain中W（P）＝W（∑P）=W（AP）的结论。     

相容连续Domain的遗传性

定义相容Domain的子Domain与子空间等概念,得到Scott开集和Scott闭集都是相容Domain的子Domain与子空间的结论,证明了相容连续Domain或相容代数Domain对开子空间和闭子空间都是可遗传的。     

连续偏序集及其Smyth幂的几个等权定理

推广连续D om a in的权的概念到连续偏序集上,探讨连续偏序集的权、相应内蕴拓扑的权、定向完备化的权以及Sm yth幂D om a in的权间的关系。得到了几个等权定理:(1)连续偏序集的权与其上Scott拓扑、L aw son拓扑的权相等;(2)连续偏序集的权与其定向完备化的权相等;(3)无穷连续D om a in的权与其Sm yth幂D om a in的权相等;(4)有限D om a in的权小于或等于它的Sm yth幂D om a in的权。     

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.     

群的一个Domain结构

群可以通过在其上赋予循环群拓扑构造群的Domain模型，从而实现群的可计算性。群上的循环群偏序集及其对偶都是连续的偏序集，这个连续偏序集是代数Domain的充分必要条件是群的单位元是代数元。如果在pseudo-有限的群G及其循环群偏序集的对偶￡^op[G]上分别赋予循环群拓扑和Scott拓扑，那么恒同函数是连续的。     

可数强F紧集的刻画与性质

借助α-ω聚点与α-聚点概念给出可数强F紧集的两个刻画定理,进而讨论可数强F紧集在L值Zadeh型函数下的逆不变性,证明了可数强F紧集与强F紧集的乘积是可数强F紧的。     

代数L-domain和强core紧空间的刻画

给出代数L-domain和强core紧空间以及连续L-domain和core紧空间的刻画。     

Continuous L-domains in logical form

We introduce a framework of approximable disjunctive propositional logic, which is the logic that results from a disjunctive propositional logic by adding an additional connective. The Lindenbaum algebra of this logic is an approximable dD-algebra. We show that for any approximable dD-algebra, its approximable filters ordered by set inclusion form a continuous L-domain. Conversely, every continuous L-domain can be represented as an approximable dD-algebra. Moreover, we establish a categorical equivalence between the category of approximable dD-algebras with approximable dD-algebra morphisms and that of continuous L-domains with Scott-continuous functions. This extends Abramsky's Domain Theory in Logical Form to the world of continuous L-domains. As an application, we give an affirmative answer to an open problem of Chen and Jung.     

A Chebyshev-Type Theorem Characterizing Best Approximation of a Continuous Function by Elements of the Sum of Two Algebras

Mathematical Notes - In the paper, we consider the problem of uniform approximation of a continuous function defined on a compact metric space $$X$$ by elements of the sum of two algebras in the...     

A Continuous Analogue of the Upper Bound Theorem

For an absolutely continuous probability measure μ on R ^d and a nonnegative integer k , let tilde s _k (μ ,origin ) denote the probability that the convex hull of k+d+1 random points which are i.i.d. according to μ contains the origin bf 0 . For d and k given, we determine a tight upper bound on tilde s _k (μ ,origin ) , and we characterize the measures in R ^d which attain this bound. As we will see, this result can be considered a continuous analogue of the Upper Bound Theorem for the maximal number of faces of convex polytopes with a given number of vertices. For our proof we introduce so-called h -functions, continuous counterparts of h -vectors of simplicial convex polytopes. Received April 14, 2000, and in revised form October 6, 2000. Online publication June 20, 2001.     

A Note on a Continuous Approximate Selection Theorem

The purpose of this note is to show a new generalization of the continuous approximate selection theorem of F. Deutsch and P. Kenderov (1983, SIAM J. Math. Anal.14, 185–194).     

局部紧Vilenkin群上Herz空间的一个分解定理

In this paper, by applying a vector-valued inequality we obtained a decomposition theorem on Herz spaces over locally compact Vilenkin groups with new range 0 < q≤1.     

A Sharp Comparison Theorem for Compact Manifolds with Mean Convex Boundary

Let M be a compact n-dimensional Riemannian manifold with nonnegative Ricci curvature and mean convex boundary ?M. Assume that the mean curvature H of the boundary ?M satisfies H≥(n?1)k>0 for some positive constant k. In this paper, we prove that the distance function d to the boundary ?M is bounded from above by \(\frac{1}{k}\) and the upper bound is achieved if and only if M is isometric to an n-dimensional Euclidean ball of radius \(\frac{1}{k}\) .     

关于紧邻域扩充性质的等价条件及其应用

本文刻画了紧邻域扩充性质的等价条件，由此条件得到如果Ｘ是具有紧邻域扩充性质的可度量化的拓扑空间，则Ｆ_ｋ（Ｘ）＝｛Ａ?Ｘ：｜Ａ｜≤ｋ｝也具有紧邻域扩充性质，此处Ｆ_ｋ（Ｘ）上的拓扑是由Ｈａｕｓｄｏｒｆ度量所诱导出的拓扑     

A Helly-Type Theorem for Intersections of Compact Connected Sets in the Plane

For a family C of nonempty compact sets in the plane, the following conditions are equivalent:(1) Every two (not necessarily distinct) members of C have a connected union and every three (not necessarily distinct) members of C have a simply connected union.(2) C is a family of simply connected sets such that every two (not necessarily distinct) members of C have a connected intersection and every three (not necessarily distinct) members of C have a nonempty intersection.If either set of conditions is satisfied, then { C : C in C } is nonempty, simply connected, and connected. Furthermore, if the collection C is finite, then it is also true that { C : C in C } is simply connected.     

紧摄动连续映象

Let X, Z be normed spaces and Ω a bounded open set in X. Suppose that I:Ω→Z is a fixed continuous bounded mapping. We discuss the properties essential and nonessential of f(x) = I(x) - F(x), see [1] p.245, where F:?Ω→Z continuous and compact.