完备主因子格

本文引入了主因子格的概念,讨论了完备主因子格中元素的结构.得到了完备主因子分配格有不可约并既分解的一个充要条件,证明了完备下连续的主因子格是有不可约并既分解的.最后讨论了完备主因子格中不可约并既分解的惟一性及可替换性,得到了完备下连续的主因子格有惟一不可约并既分解或者有可替换不可约并既分解的一些充要条件.     

完备主因子格上的不可约并既分解

讨论了完备主因子格的一些结构性质,得到了完备分配格有不可约并既分解及不可约完全并既分解和不可约连续并既分解的一些充要条件。     

并素元有限生成格的弱直积分解

本文建立了并素元有限生成格的弱直积分解,并给出一个解决并素元生成的完全Heyting代数的直积分解问题的新方法;作为弱直积分解的应用,证明了并素元有限生成的完全Heyting代数必然同构于有限个既约的完全Heyting代数的直积,证明了并素元有限生成格是Boole代数的充要条件是它同构于某有限集的幂集格.     

一类完备格的直积分解与Fuzzy格的构造

本文主要结果为:1.以拓扑空间的连通分支为工具,证明了由并素元生成的完全Heyting代数存在既约的直积分解,并且它的任意两个既约直积分解是等价的,从而推广了[1]的主要结果;2.利用完全分配格的既约直积分解,得到Fuzzy格的一个构造定理,并在此基础上讨论Fuzzy格的直积分解,证明了任一Fuzzy格存在既约直积分解,并在序同构的意义下是唯一的.     

每个元有上覆盖的紧生成格的结构

Dilwrorth与Crawleyl973年提出能否去掉上半模格条件来刻画元素的不可约完全交既分解问题以及能否去掉强原子格的条件刻画紧生成格结构的问题,本文首先证明了每个元有上覆盖的紧生成格L中任意元有不可约完全交既分解,从而肯定地回答了Dilworth与Crawley上述第一个问题.之后,在每个元有上覆盖的紧生成格中引入局部强模格与局部强分配格的概念,研究了局部强模格中独立集的特性以及局部强模格与局部分配格的结构,从而部分解决了Dilworth与Crawley上述第二个问题.     

含有对数非线性项的p-Laplace方程的多重解

主要通过变分方法研究了有界区域上含有变号权函数和对数非线性项的一类p-Laplace方程Dirichlet边值问题的多解性.通过分解能量泛函的Nehari流形,利用对数Sobolev不等式,极小化序列方法及相关知识证明了能量泛函至少存在两个非零极小元,从而证明了问题至少存在两个非平凡解.     

L_n×L_2上几类特殊类型格蕴涵代数方程的解法

在格蕴涵代数中提出了加既约元、乘既约元,研究了一类重要的格蕴涵代数L_n×L_2中元素的不可约有限分解, 并将这一理论用于研究L_n×L_2上的几类格蕴涵代数方程,讨论了方程有解的充分必要条件,在此基础上给出了方程的具体解集.     

矩阵方程AXAT=C的对称斜反对称解

设A∈Rm×n,C∈Rm×m给定,利用矩阵的广义奇异值分解和对称斜反对称矩阵的性质,得到了矩阵方程(1)AXAT=C存在对称斜反对称解的充要条件和通解表达式;证明了若方程(1)有解,则一定存在唯一极小范数解,并给出了极小范数解的具体表达式和求解步骤.     

超平面构形的可约性

解决了关于中心超平面构形可约性的几个问题.首先,得到了可约性的一个充分必要条件. 具体地说,证明了中心超平面构形的不可约分支数等于构形的零次与一次对数导子所张成向量空间的维数.其次,证明了在相差背景空间的一个同构下,构形分解为不可约分支的直和的分解方式是唯一的.第3,给出了决定不可约分支个数和将构形分解成不可约分支之直和的一个有效算法.用此算法可决定一个构形是否可约.在可约情形下可以得到各个不可约分支的定义方程.     

有限域上n元n次方程只有零解的充要条件

本文研究了有限域上只有零解的n元n次方程的结构问题.利用对有限域上不可约多元多项式在其扩域中的分解特征的刻画,结合Chevalley定理,得到了有限域上n元n次方程只有零解的一个充要条件,并给出这类方程的一些新的具体构造.     

The solution sets of infinite fuzzy relational equations with sup-conjunctor composition on complete distributive lattices

This paper deals with sup-conjunctor composition fuzzy relational equations in infinite domains and on complete distributive lattices. When its right-hand side is a continuous join-irreducible element or has an irredundant continuous join-decomposition, a necessary and sufficient condition describing an attainable solution (resp. an unattainable solution) is formulated and some properties of the attainable solution (resp. the unattainable solution) are shown. Further, the structure of solution sets is investigated.     

Minimal covers,minimal sets and canonical facets of the posynomial knapsack polytope

An irredundant representation of the 0–1 solutions to a posynomial inequality in terms of covering constraints induced by minimal covers is given. This representation is further strengthened using extended covering constraints induced by maximal extensions of minimal covers. Necessary, sufficient, and in a special case necessary and sufficient conditions for an extended covering constraint induced by a minimal set to be a facet of the posynomial knapsack polytope are given.     

Method of solution to fuzzy relation equations in a complete Brouwerian lattice

Up to now, how to solve a fuzzy relation equation in a complete Brouwerian lattice is still an open problem as Di Nola et al. point out. To this problem, the key problem is whether there exists a minimal element in the solution set when a fuzzy relation equation is solvable. In this paper, we first show that there is a minimal element in the solution set of a fuzzy relation equation AX=b (where A=(a₁,a₂,…,a_n) and b are known, and X=(x₁,x₂,…,x_n)^T is unknown) when its solution set is nonempty, and b has an irredundant finite join-decomposition. Further, we give the method to solve AX=b in a complete Brouwerian lattice under the same conditions. Finally, a method to solve a more general fuzzy relation equation in a complete Brouwerian lattice when its solution set is nonempty is also given under similar conditions.     

Intervals in Lattices of κ-Meet-Closed Subsets

We study abstract properties of intervals in the complete lattice of all κ-meet-closed subsets (κ-subsemilattices) of a κ-(meet-)semilattice S, where κ is an arbitrary cardinal number. Any interval of that kind is an extremally detachable closure system (that is, for each closed set A and each point x outside A, deleting x from the closure of A∪{x} leaves a closed set). Such closure systems have many pleasant geometric and lattice-theoretical properties; for example, they are always weakly atomic, lower locally Boolean and lower semimodular, and each member has a decomposition into completely join-irreducible elements. For intervals of κ-subsemilattices, we describe the covering relation, the coatoms, the ∨-irreducible and the ∨-prime elements in terms of the underlying κ-semilattices. Although such intervals may fail to be lower continuous, they are strongly coatomic if and only if every element has an irredundant (and even a least) join-decomposition. We also characterize those intervals which are Boolean, distributive (equivalently: modular), or semimodular. Mathematics Subject Classifications (2000) Primary: 06A12; Secondary: 06B05, 06A23, 52A01.     

On the classical and generalized solutions of boundary-value problems for difference-differential equations with variable coefficients

The first boundary-value problem for second-order difference-differential equations with variable coefficients on a finite interval (0, d) is considered. The following question is studied: Under what conditions will the boundary-value problem for a difference-differential equation have a classical solution for an arbitrary continuous right-hand side? It is proved that a necessary and sufficient condition for the existence of a classical solution is that certain coefficients of the difference operators on the orbits generated by the shifts be equal to zero.     

Irredundant and Minimal Covers of Finite Groups

A cover of a finite noncyclic group G is a family ? of proper subgroups of G whose union equals G. A cover of G is called minimal if it has minimal size, and irredundant if it does not properly contain any other cover. We classify the finite noncyclic groups all of whose irredundant covers are minimal.     

Sub(L)中的五边形格特征及其数量不等式

五边形结构在刻画格的特征方面具有十分重要作用，应用格论及组合数学的方法讨论了格L与其子格格Sub(L)中所含五边形格之间的数量关系，给出了有限格L的子格格中三个元生成五边形格的充要条件，同时给出了Sub(L)所含不同五边形格数量的一个下界。     

Minimum-Euclidean-norm matrix correction for a pair of dual linear programming problems

For a pair of dual (possibly improper) linear programming problems, a family of matrix corrections is studied that ensure the existence of given solutions to these problems. The case of correcting the coefficient matrix and three cases of correcting an augmented coefficient matrix (obtained by adding the right-hand side vector of the primal problem, the right-hand-side vector of the dual problem, or both vectors) are considered. Necessary and sufficient conditions for the existence of a solution to the indicated problems, its uniqueness is proved, and the form of matrices for the solution with a minimum Euclidean norm is presented. Numerical examples are given.     

Matrix correction of a dual pair of improper linear programming problems

A matrix is sought that solves a given dual pair of systems of linear algebraic equations. Necessary and sufficient conditions for the existence of solutions to this problem are obtained, and the form of the solutions is found. The form of the solution with the minimal Euclidean norm is indicated. Conditions for this solution to be a rank one matrix are examined. On the basis of these results, an analysis is performed for the following two problems: modifying the coefficient matrix for a dual pair of linear programs (which can be improper) to ensure the existence of given solutions for these programs, and modifying the coefficient matrix for a dual pair of improper linear programs to minimize its Euclidean norm. Necessary and sufficient conditions for the solvability of the first problem are given, and the form of its solutions is described. For the second problem, a method for the reduction to a nonlinear constrained minimization problem is indicated, necessary conditions for the existence of solutions are found, and the form of solutions is described. Numerical results are presented.