交换偏序半群的偏序扩张

设(S,·,≤)为偏序可换半群,本文给出将S的偏序≤扩张为满足一定条件的偏序≤^{*的充要条件.特别地,如果(S,·,≤)为可消偏序可换幺半群,本文给出将S的偏序≤扩张为可消偏序≤*且S的每个元素在≤*下均在正锥中的充要条件.本文还给出将偏序可换幺半群S的偏序≤扩张为≤*且使得S的有限元素子集在≤*下是一条链的充要条件.}     

可数S_2-拟连续偏序集北大核心CSCD

作为广义可数逼近偏序集与S2-拟连续偏序集的共同推广,引入了可数S2-拟连续偏序集的概念并讨论了它的一些性质.本文的主要结果:(1)可数S2-拟连续偏序集上的可数way below关系满足插入性质;(2)可数S2-拟连续偏序集关于其上的弱σ-Scott拓扑为局部紧致的可数sober空间;(3)偏序集P为可数S2-连续偏序集当且仅当P为可数S2-交连续的可数S2-拟连续偏序集.     

逆半群半格上的自然偏序关系

首先讨论逆半群Sa的半上的自然偏序与各Sa上的自然偏序之间的关系，然后讨论逆半群Sa的半格S的幂等元集Ea的闭包限制在Sa上与Ea的闭包的关系．     

偏序半群的最大自然序半格同态象

引进了自然序半格，偏序半群的自然序半格同态象和二次主根基等概念，利用二次主根基构造出了任意偏序半群的最大自然序半格同态象。     

交C-连续偏序集

利用偏序集上的半拓扑结构,引入了交C-连续偏序集概念,探讨了交C-连续偏序集的性质、刻画及与C-连续偏序集、拟C-连续偏序集等之间的关系.主要结果有:(1)交C-连续的格一定是分配格;(2)有界完备偏序集(简记为bc-poset)L是交C-连续的当且仅当对任意x∈L及非空Scott闭集S,当∨S存在时有x∧∨S=∨{x∧s:s∈S};(3)完备格是完备Heyting代数当且仅当它是交连续且交C-连续的;(4)有界完备偏序集是C-连续的当且仅当它是交C-连续且拟C-连续的;(5)获得了反例说明分配的完备格可以不是交C-连续格,交C-连续格也可以不是交连续格.     

富足半群上的自然偏序

本文研究富足半群上的自然偏序，得到Green关系和自然偏序之间的联系，确定了富足半群何时关于自然偏序具有单边(双边)相容，另外，也研究了富足半群的本原元。     

可数S_2-拟连续偏序集

作为广义可数逼近偏序集与S2-拟连续偏序集的共同推广,引入了可数S2-拟连续偏序集的概念并讨论了它的一些性质.本文的主要结果:(1)可数S2-拟连续偏序集上的可数way below关系满足插入性质;(2)可数S2-拟连续偏序集关于其上的弱σ-Scott拓扑为局部紧致的可数sober空间;(3)偏序集P为可数S2-连续偏序集当且仅当P为可数S2-交连续的可数S2-拟连续偏序集.     

乘法半群为左正规纯正群的半环

研究了加法半群为半格,乘法半群为左正规纯正群的半环．证明了此类半环（S,＋,．）可以嵌入到半格（S,＋）的自同态半环中．构造S的一个特定的偏序关系,得到了（S,·）上的自然偏序与所构造偏序相等的等价条件．     

S-定向完备偏序集范畴

给出定向完备偏序半群的定义,研究定向完备偏序半群在定向完备偏序集上的作用.探讨S-定向完备偏序集范畴的一些基本性质,并且证明以S-定向完备偏序集为对象,以S-Scott连续映射为态射的范畴是笛卡尔闭范畴.     

具有Q-正则*-断面的正则半群的自然偏序

刻画了具有Q-正则*-断面的正则半群的自然偏序,并得到.该类半群上自然偏序满足(纫)-优化(劣化),ρ-优化(劣化)的条件.     

On congruences and ideals of partially ordered quasigroups

Some results concerning congruence relations on partially ordered quasigroups (especially, Riesz quasigroups) and ideals of partially ordered loops are presented. These results generalize the assertions which were proved by Fuchs in [5] for partially ordered groups and Riesz groups.     

The Hahn–Banach Theorem for Partially Ordered Totally Convex, Positively Convex and Superconvex Modules

The Hahn–Banach Theorem for partially ordered totally convex modules [3] and a necessary and sufficient condition for the existence of an extension of a morphism from a submodule C ₀ of a partially ordered totally convex module C (with the ordered unit ball of the reals as codomain) to C, are proved. Moreover, the categories of partially ordered positively convex and superconvex modules are introduced and for both categories the Hahn–Banach Theorem is proved.     

Splittability for Partially Ordered Sets

A topological space X is said to be splittable over a class P of spaces if for every AX there exists continuous f:XYP such that f(A)f(XA) is empty. A class P of topological spaces is said to be a splittability class if the spaces splittable over P are precisely the members of P. We extend the notion of splittability to partially ordered sets and consider splittability over some elementary posets. We identify precisely which subsets of a poset can be split along over an n-point chain. Using these results it is shown that the union of two splittability classes need not be a splittability class and a necessary condition for P to be a splittability class is given.     

On Relationships Between Semi- antichains andUnichain Coverings in Discrete Mathematics

§1.　IntroductionTherelationsbetweenchainsandantichainsinapartiallyorderedsetaretheextensionoftheconceptssuchas“selectingrepresentation”,“selectingseedings”andetc.inrealworldinpractice.Theyaretherelationstobeconsideredindesigningsystems.LetPandGbetwopartiallyorderedsets.Thepartiallyorderedrelation[1]onthemarere-spectivellyrepresentedby“≤”(Theirmeaningsmaybedifferentinpracticeindifferentpar-tiallyorderedset).ThedirectproductP×GofPandGisdefinedasfollows:P×G={(p,g)|p∈P,g∈G}.Thep…     

Axiomatizability and completeness of some classes of partially ordered polygons

We study partially ordered monoids over which a class of free (over sets and over posets), projective, and (strongly, weakly) flat partially ordered polygons is axiomatizable, complete, or model complete. Similar issues for polygons were dealt with in papers by V. Gould and A. Stepanova. Supported by the Council for Grants (under RF President) and State Aid of Leading Scientific Schools (grant NSh-2810.2008.1). Translated from Algebra i Logika, Vol. 48, No. 1, pp. 90–121, January–February, 2009.     

Fuzzy Ordered Filters in Implicative Semigroups

Animplicativesemilatticeisanalgebraicsystemhavingasmodelslogicalsystemsequippedwithimplicationandconjunction,butnotpossessingadisjunction.ImplicativesemilatticeswerestudiedbyW.C.Nemitz[5].In[2],T.S.BlythgeneralizedsomeresultsofW.C.Nemitz[5]byintroducingthenotionofaBrouweriansemigroup.FollowingtheideasofNemitzandBlyth,M.W.ChanandK.P.Shum[3]introducedthenotionofnegativelypartiallyorderedimplicativesemigroupsandgeneralizedsomeresultofNemitzonimplicativesemilatticestoim-plicativesemigroups…     

PARTIALLY ORDERED CONNECTIVES

We show that a coherent theory of partially ordered connectives can be developed along the same line as partially ordered quantification. We estimate the expressive power of various partially ordered connectives and use methods like Ehrenfeucht games and infinitary logic to get various undefinability results.     

On Operations and Linear Extensions of Well Partially Ordered Sets

A (partially) ordered set P is well founded if no infinite decreasing sequences occur in P. A well founded poset containing no infinite antichains is called partially well ordered. We investigate some operations preserving that property and linear extensions of partial well orders. This revised version was published online in September 2006 with corrections to the Cover Date.     

Extensions of lattice-ordered groups

A number of conditions are specified which are sufficient for totally ordered groups with polycyclic factor group to contain a finite normal series of convex subgroups whose factors possess good enough properties. In any case studying such totally ordered groups is reduced to treating extensions of these groups as well as their virtually o-equivalent extensions. The concept of a virtually o-equivalent extension is a particular case of the notion of an Archimedean extension. Supported by RFBR project No. 03-01-00320. Translated from Algebra i Logika, Vol. 47, No. 5, pp. 529–540, September–October, 2008.