α-对角占优与广义严格对角占优矩阵的判定

1 引言与记号 广义严格对角占优矩阵在数学、物理、控制论及经济学等许多领域有着重要的研究价值和实用价值.广义严格对角占优矩阵就是非奇异日一矩阵,它是一类范围很广的特殊矩阵,熟知的严格对角占优矩阵,不可约对角占优矩阵,非奇异M-矩阵等都是其特殊情形.如何在实际应用中简便地判别一个矩阵是否是日一矩阵,一直是人们关注的问题.     

H-矩阵的一组新判定

非奇H矩阵在众多领域有着重要的应用,但其判别却很困难.本文给出了非奇异H-矩阵若干个新的判据.推广了近期的相应结果.     

广义严格对角占优矩阵的一种判别法

广义严格对角占优矩阵是一类很重要的特殊矩阵,在理论与实际中具有广泛的应用,有关它的判别一直是人们研究的重点.本文给出广义严格对角占优矩阵的一种迭代判别法,证明了相应的收敛性理论,并用数值算例展示了该判别法的有效性.     

H-矩阵的判别法及其迭代算法

通过对方阵行下标集不同的递进式划分,我们获得了H-矩阵几个新的判别法,进而给出H-矩阵的迭代判别法,最后利用数值例子说明这些判别法的有效性.     

广义严格对角占优矩阵的几个判定条件

广义严格对角占优矩阵在计算数学、数学物理、控制论等众多领域有着广泛而重要的应用.但实际判断一个矩阵是否为广义严格对角占优矩阵却是困难的.本文利用α-对角占优矩阵的性质,给出了广义严格对角占优矩阵的几个判定条件,扩大了判别范围.     

论几类广义严格对角占优矩阵

1引言 设A=（a_η）∈Cm~(3n),若存在正对角阵D.使得AD为严格对角占优矩阵，则A称为广义严格对角占优矩阵，记作A∈SGDDM.     

H-矩阵的实用判定

H-矩阵在许多领域中都发挥着重要作用，但在实用中要判别H-矩阵却是很困难的．本文中，我们获得了H-矩阵判别的新的实用充分条件，所得结果包含了[1]的一个主要结果，并用例子说明了文中结果的有效性.     

广义严格对角占优阵的判定程序

1 引言和符号 在本文中,均采用下列符号而不再重申.恒用N表示前n个自然数的集合;而用Mn(C)和Mn(R)分别表示所有n阶复矩阵和所有n阶实矩阵的集合. Z_N={A|A=(a_(ij))_(n×n)∈Mn(R),a_(ij)≤0,i,j∈N,i≠j},I恒表示单位矩阵. 如果A∈Mn(R)且A的所有元素都为非负实数,则称A为非负方阵,并记为A≥0;若A的所有元素都为正数,则称A为正矩阵,并记为A>0. 对A=(a_(ij))(n×n)∈Mn(C),令A_i(A)=sum from j=1 j≠i to n (|a_(ij)|(i=1、2…… n)) ;若把A的非零元用1代替 而得到—个n阶(0,1)矩阵。称为A的导出矩阵。记为;而把A的比较矩阵记为 u(A)=(b_(ij))_(n×n))其中b_(ij)=|a_(ij)|,b_(ij)=-|a_(ij)|(i,j∈N i≠j)     

广义严格对角占优矩阵的充分条件

1 引言 广义严格对角占优矩阵是一类在数值代数、数学物理和控制论等领域有着广泛应用的特殊矩阵,例如:线性方程组Ax=b,当系数矩阵A为广义严格对角占优矩阵时,许多经典的迭代算法均是收敛的,同时对目前提出的一些修正算法也是收敛的.     

正项矩阵级数的敛散性研究

本文研究了正项矩阵级数收敛的充要条件 ,从而把正项级数的收敛原理推广到了正项矩阵级数的情形 .     

On commutativity of near-rings with generalized derivations

In this paper we prove some theorems of commutativity for near-rings with generalized derivations. As a consequence of the results obtained, we generalize some published results. Also, we give some examples to show that some conditions in some results obtained are not redundant.     

关于一个奇异Dirichlet问题的注记

The Dirichlet problem to a second order differential equation with some singularities is studied. Some existence results are established to the problem which generalize some results recently obtained by D. O‘Regan by eliminating some superfluous constrains to the problem. Also, some new results have been proven which may provide more useful information for the study of the problem.     

Nontrivial solutions for resonant cooperative elliptic systems via computations of the critical groups

In this paper, we consider a class of resonant cooperative elliptic systems. Based on some new results concerning the computations of the critical groups and the Morse theory, we establish some new results about the existence and multiplicity of solutions under new classes of conditions. It turns out that our main results sharply improve some known results in the literature.     

Existence and global attractivity of solutions of a nonlinear functional integral equation

This paper presents some results concerning the existence, uniform local attractivity and global attractivity of solutions for a functional integral equation, via measure of noncompactness. Our results improve and extend some previous results obtained in other studies. We will also include some examples which show that our results are applicable where the previous ones are not.     

关于一类偶数阶半线性微分方程解的振动性的注记

通过运用分析方法,对微分不等式进行估计,得到了一类偶数阶半线性微分方程解的振动性的若干判别准则.所得结果减弱了已有文献的条件,推广和改进了已有文献的结果.     

一类二阶非线性微分方程解的零点比较定理

通过建立几个微分不等式将经典的微分方程零点比较定理推广到二阶非线性微分方程,得到若干新的结论.     

On the solutions of a second order nonlinear system with almost periodic forcing

A second order almost periodic perturbed nonlinear system with small parameter is discussed in this paper. Based on some analytical techniques and the method of averaging, some sufficient conditions are obtained for existence of one almost periodic solution. Also some suitable conditions are given for existence of two almost periodic solutions. The obtained new results generalized the known results in Seifert [1], [3] and He [2], [4]. Finally, some applications are presented to illustrate that our results are a good generalization of the known results.     

The multiplicity of solutions for perturbed second-order Hamiltonian systems with impulsive effects

In this paper, we study the existence of multiple solutions for a class of second-order impulsive Hamiltonian systems. We give some new criteria for guaranteeing that the impulsive Hamiltonian systems with a perturbed term have at least three solutions by using a variational method and some critical points theorems of B. Ricceri. We extend and improve on some recent results. Finally, some examples are presented to illustrate our main results.     

STUDY OF PERIODIC SOLUTIONS OF FOURTH ORDER NDE WITH DELAYS

Using Fourier series theory and techniques of real analysis inequality, some sufficient conditions of existence and uniqueness of periodic solutions for a class of fourth order neutral differential equations with some delays are obtained, the results extend and improve some known results.     

OSCILLATION CRITERIA FOR EVEN ORDER DELAY DIFFERENTIAL EQUATIONS WITH NONLINEAR TERM

By Riccati transformation, we establish some new oscillation criteria for a class of even order delay differential equations with nonlinear term. In some sense, the results obtained extend some known results in the literature.