Z-连通代数偏序集及其范畴

对于Z-连通集系统,本文引入了Z-连通代数偏序集的概念,证明了Z-连通代数偏序集范畴对偶等价于强代数格范畴的一个满子范畴.     

H-代数偏序集

本文引入了H-代数偏序集的概念,讨论了它的一些基本性质.得到如下主要结果:(1)举例说明了代数偏序集未必是H-代数偏序集;(2)偏序集是H-代数偏序集当且仅当强紧元是它的强基;(3)偏序集是H-代数偏序集当且仅当它的局部Scott拓扑是强代数格.     

强代数偏序集

引入了一种新的强代数偏序集的概念,证明了偏序集P为强代数的当且仅当其正规完备化δ(P)为强代数格,给出了强代数偏序集的内蕴式刻画。     

偏序集代数的同构问题

在[1]中对局部有限偏序集I={I,≤}及域K引入了关联代数KI的概念.这里的“局部有限”是指对任意a,b∈I,a≤b,集合{x∈I|a≤x≤b}.是有限集.KI的定义是:其元素是域K上以I中元素为行与列的足码的形式矩阵(кa,b)a,b∈I,(即允许有无限多个ka,b≠0)且满足条件:当a≮b时有ka,b=0.注意到I的局部有限性,易知上述形式矩阵的全体关于通常矩阵的加法和乘法以及数乘作成域K上的一个结合代数,称之为I在K上的关联代数KI。     

HC-偏序集的若干性质

基于超连续格的内蕴式刻画,引入HC-偏序集的概念,讨论了HC-偏序集的一些性质.类似地,作为超代数格的推广,引入了HA-偏序集并讨论其相关性质.     

C_Z-偏序集

我们将强Z-连续偏序集推广到了CZ-偏序集,并讨论了CZ-偏序集和强Z-连续偏序集之间的关系。同时我们定义了CZ-偏序集上的CZ-连续映射,得到CZ-偏序集在该映射下的像集仍是CZ-偏序集。最后,我们讨论了CZ-偏序集上的基及其相关性质。     

强Raney偏序集

引入强Raney偏序集的概念,讨论了强Raney偏序集的一些性质,证明了强Raney偏序集为超代数偏序集,定向完备的偏序集为强Raney偏序集当且仅当它既是Raney偏序集也是A-偏序集.     

伪超连续偏序集

引入了伪超连续偏序集和伪超代数偏序集的概念,讨论了它们的一些基本性质,给出了它们的若干刻画,特别是基于区间拓扑、某种特殊二元关系的刻画和内蕴式刻画.     

R-偏序集上的cpo,代数cpo与连续cpo

本文研究了若干结构在R-偏序集上的保持性.利用例子说明了R-偏序集所带的偏序族在逼近某个偏序时未必保持cpo,代数cpo或连续cpo等结构,并给出了使得代数cpo和连续cpo结构得以保持的充分条件.     

Z-连通连续偏序集的特征和浓度

引入了Z-连通连续偏序集的局部基和稠密子集的概念,给出了局部基的一些刻画,在此基础上定义了Z-连通连续偏序集的特征和浓度。证明了Z-连通连续偏序集的特征和浓度与Z-连通连续偏序集带上Scott拓扑时的拓扑空间的特征和浓度相等,它们分别小于Z-连通连续偏序集带上Lawson拓扑时拓扑空间的特征、浓度。     

Generalized Continuous Posets and a New Cartesian Closed Category

With every subset selection for posets, there is associated a certain ideal completion . As shown by Erné, such completions help to extend classical results on domains and similar structures in the absence of the required joins. Some results about –predistributive or –precontinuous posets and –continuous functions are summarized and supplemented. In particular, several central results on function spaces in domain theory are extended to the setting of productive closed subset selections. The category FSBP, in which objects are finitely separated and upper bounded posets and arrows are continuous functions between them, is shown to be cartesian closed. This research is supported by the National Natural Science Foundation of China, 10471035.     

Z-连通集系统及其范畴特征

本文引入了Z-连通集系统的概念,讨论了Z-连通连续偏序集的一系列性 质,证明了Z-连通连续偏序集范畴对偶等价于完全分配格范畴的一个满子范畴.     

偏序集的代数完备

引进一个偏序集的代数完备, 并且构造任意偏序集的一个代数完备.有最小元的并半格的代数完备正好是它的理想完备. 一个偏序集的代数完备同构于它的一个由下集作为元的完备格,并且这个完备格包含所有主理想. 基于代数完备的Galois联络的下扩张仍然是一个Galois联络.     

Z-连续偏序集的表示定理

在偏序集中引入嵌入Z-基并根据嵌入Z-基建立Z-连续偏序集的表示定理.同时,我们将讨论抽象Z-基的Z-理想完备是Z-代数偏序集的条件.最后,我们深入探讨嵌入Z-基、Z-连续扩张和σz-集之间的关系.     

偏序集的零调性与可缩性

本文将给出偏序集零调与可缩的几个充分条件，它们包含和深化了文［１］和［２］中的一些结果，把［２］中的一些结果推广到无限偏序集的情形．     

The Involutory Dimension of Involution Posets

The involutory dimension, if it exists, of an involution poset P:=(P,,) is the minimum cardinality of a family of linear extensions of , involutory with respect to , whose intersection is the ordering . We show that the involutory dimension of an involution poset exists iff any pair of isotropic elements are orthogonal. Some characterizations of the involutory dimension of such posets are given. We study prime order ideals in involution posets and use them to generate involutory linear extensions of the partial ordering on orthoposets. We prove several of the standard results in the theory of the order dimension of posets for the involutory dimension of involution posets. For example, we show that the involutory dimension of a finite orthoposet does not exceed the cardinality of an antichain of maximal cardinality. We illustrate the fact that the order dimension of an orthoposet may be different from the involutory dimension.     

The Semimodularity of Cardinal Power of Posets

LetX,Ybeanyposets,Y'denotethecardinalpowerwithbaseYandexponentX.Fortherelatedconceptslsymbolsorterminologies,seeF1],[2jor[3].lnL1],someexamplesaregaven,whichshowthatthesemimodularityofX,YandYxareindepentent.AndaquestionisaskedthatwhenthecardinalpowerYxwithbaseYandexpo-nentXissemimodular.Wenowanswerthequestioninthispaper.LemmaLetX,Ybeanyposets,f,geyx,thenthefollowingconditionsareequivalent:(l)fiscoveredbyg(denotedbyf,g);(2)Thereexists'anelementxoeX,suchthatf(x,),g(x,),andf(x)=g(x)(foran…     

Partitioning Posets

Given a poset P = (X, ≺ ), a partition X ₁, ..., X _k of X is called an ordered partition of P if, whenever x ∈ X _i and y ∈ X _j with x ≺ y, then i ≤ j. In this paper, we show that for every poset P = (X, ≺ ) and every integer k ≥ 2, there exists an ordered partition of P into k parts such that the total number of comparable pairs within the parts is at most (m − 1)/k, where m ≥ 1 is the total number of edges in the comparability graph of P. We show that this bound is best possible for k = 2, but we give an improved bound, , for k ≥ 3, where c(k) is a constant depending only on k. We also show that, given a poset P = (X, ≺ ) and an integer 2 ≤ k ≤ |X|, we can find an ordered partition of P into k parts that minimises the total number of comparable pairs within parts in time polynomial in the size of P. We prove more general, weighted versions of these results. Supported by an EPSRC doctoral training grant.