弱射影与De Morgan代数的同余关系

本文借助弱射影和弱透视的概念刻划了Ｄｅ Ｍｏｒｇａｎ代数的同余关系,由此得到了Ｋａｌｍａｎ关于Ｄｅ Ｍｏｒｇａｎ代数次直不可约定理的一个新的证明并证明了一个完全分配的Ｄｅ Ｍｏｒｇａｎ代数的同余理想与同余关系一一对应的充要条件是Ｌ为弱可补的。     

双极值模糊集在半环上的应用

On the basis of concepts of bipolar fuzzy sets, we establish a new framework of bipolar fuzzy subsemirings（resp., ideals） which is a generalization of traditional fuzzy subsemirings（resp., ideals） in semirings. The concepts of bipolar fuzzy subsemirings（resp., ideals） are introduced and related properties are investigated by means of positive t-cut, negative s-cut and equivalence relation. Particularly, the notion of a normal bipolar fuzzy ideal is given, and some basic properties are studied in this paper.     

Subtraces and shadow chains

Given a finite algebra A, such that the variety omits type 1, it is shown that type 5 will occur in only if type 5 already occurs in the free algebra on two generators. The technique generalizes to give the decidability of other typesets, and provides a simpler alternative to what had previously required Maltsev conditions. Received October 9, 1998; accepted in final form January 29, 1999.     

1. Introduction

In this paper, we give the conception of implicit congruence and nonimplicit congruence in a unique factorization domain R and establish some structures of irreducible polynomials over R. A classical result, Eisenstein's criterion, is generalized.     

The lattice of idempotent distributive semiring varieties

A solution is given for the word problem for free idempotent distributive semirings. Using this solution the latticeL (ID) of subvarieties of the variety ID of idempotent distributive semirings is determined. It turns out thatL (ID) is isomorphic to the direct product of a four-element lattice and a lattice which is itself a subdirect product of four copies of the latticeL(B) of all band varieties. ThereforeL(ID) is countably infinite and distributive. Every subvariety of ID is finitely based. Project supported by the National Natural Science Foundation of China (Grant No. 19761004) and the Provincial Applied Fundamental Research Foundation of Yunnan (96a001z).     

拟正则半群的圈积嵌入与矩阵同余

给出了拟正则半群的圈积嵌入．研究了幂等元集 Ｅ Ｓ 生成的子半群〈 Ｅ Ｓ〉上的矩阵同余可扩张为 Ｓ上的矩阵同余的条件． 特别地,如果〈 Ｅ Ｓ〉上的最小矩阵同余可扩张为 Ｓ上的矩阵同余,那么〈 Ｅ Ｓ〉上的每个矩阵同余可扩张为 Ｓ上的矩阵同余     

PMS-代数中的正则理想

本文提出伪补 Ｍ Ｓ 代数（简称 Ｐ Ｍ Ｓ 代数）中正则理想、正则同余关系的概念,研究正则理想与核理想、０ 理想之间的关系,讨论正则同余关系的性质,得到若干结果     

半群的子半群上的同余扩张(英)

设ρ是个群S上的一个同余．如果S／ρ是矩形带,则称ρ是矩形带同余。本文刻画了半群上的最小矩形带同余．设T是半群S的子半群,本文给出了T上每个矩形带同余能扩张成S上矩形带同余的充分必要条件。     

关于平行可分解格

本文对任意两个平行元素都满足分解特性的平行可分解格进行了研究,证明了这种格可表为有最小元的全序集簇的亚直积,而且得到它的许多有趣的性质。     

集束光水下图像系统

报道了一种新型的适用于浑水条件下的集束光水下图像系统.分析了目前水下观察采用的两种技术—同步扫描技术和距离选通技术,介绍了该水下图像系统的构成原理以及系统组成.通过水池实验,验证了系统的有效性.给出了集束光水下图像系统与水下激光图像系统在探测距离及其它性能方面的比较结果.该系统有望在海洋工程及军事上得到广泛应用.