Hermite正定矩阵迹的几个重要不等式

本文研究了Hermite正定矩阵迹的不等式问题.利用文献[1、2]的部分结果和矩阵恒等变形的方法,得到了关于Hermite正定矩阵迹的几个重要不等式,推广了文献[5、6]的结果     

具有无界分段常矩阵的三阶微分方程及其扰动方程的指数

关于对具有分段常矩阵的微分方程的研究,等人在文献[1]—[5]中给出了一些重要结果,文献[1]—[3]主要研究了有界情形,文献[4]、[5]研究了二阶无界分段常矩阵情形.本文将讨论三阶无界分段常矩阵情形,给出了其解的指数的上、下界和具有上、下界指数的解的存在性;最后还研究了其扰动方程的解的指数.     

Hermite正定对称矩阵迹的一些结果(英文)

本文研究了一类Hermite正定矩阵迹的不等式问题.利用文献[2-6]中的结果以及放缩法,获得了Hermite正定矩阵迹的极值定理、杨氏不等式和贝努利不等式,并且将许多初等不等式推广到Hermite正定矩阵迹的情形.     

矩阵之和的特征值与奇异值估计

本文获得了矩阵之和的特征值与奇异值的若干不等式，推广了文献[1]-[3]中的相关结果．     

复正定矩阵的行列式不等式

本文指出了文献[3-6]中的一些不正确的结论,并给出了复正定矩阵的行列式不等式.     

矩阵函数的性质

研究矩阵函数的若干性质,推广了文献[1]的部分结果.     

具有最大连续指数集的本原矩阵类

设 E_n 为 n 阶本原矩阵类的指数集,[1,λ_n]为 E_n 中的一个最大连续指数集.本文证明了存在某一类矩阵,它具有最大连续指数集[1,λ_n],从而完全解决了文献[1]中提出的两个问题.     

Hermite矩阵迹的几个不等式

本文研究了一类Hermite矩阵迹的不等式问题.利用J.R.Magnus在文献[4]中介绍的部分结果及其一些初等不等式,结合矩阵恒等变形的方法,得到了关于Hermite矩阵迹的一些与这些初等不等式平行的不等式.     

共轭广义对角占优矩阵的特征值分布

文献[1]和[2]分别给出了复方阵A在准严格对角占优和共轭准严格对角占优(由定义知它包含了严格对角占优类和共轭严格占优类)条件下的特征值分布。[6]对此作了进一步的研究。这些结果对矩阵特征值理论和特殊矩阵理论有着重要的意义。 本文导出了复方阵A在广义对角占优和共轭广义对角占优条件下的特征值分布。由于广     

二阶分块矩阵的伴随矩阵

本文主要讨论二阶分块矩阵的伴随矩阵,考虑到任何矩阵无论是否可逆,均存在伴随矩阵,将文献[1]中可逆的情况推广到了较一般情况,得到了二阶分块矩阵伴随矩阵的有关结论,并改进了文献[2]中相关结论的证明过程.     

Perturbation Theory for Simultaneous Bases of Singular Subspaces

New perturbation theorems are proved for simultaneous bases of singular subspaces of real matrices. These results improve the absolute bounds previously obtained in [6] for general (complex) matrices. Unlike previous results, which are valid only for the Frobenius norm, the new bounds, as well as those in [6] for complex matrices, are extended to any unitarily invariant matrix norm. The bounds are complemented with numerical experiments which show their relevance for the algorithms computing the singular value decomposition. Additionally, the differential calculus approach employed allows to easily prove new sin perturbation theorems for singular subspaces which deal independently with left and right singular subspaces.     

Estimates for the inverse elements of tridiagonal matrices

In this work, new upper and lower bounds for the inverse entries of the tridiagonal matrices are presented. The bounds improve the bounds in D. Kershaw [Inequalities on the elements of the inverse of a certain tridiagonal matrix, Math. Comput. 24 (1970) 155–158], P.N. Shivakumar, C.X. Ji [Upper and lower bounds for inverse elements of finite and infinite tridiagonal matrices, Linear Algebr. Appl. 247 (1996) 297–316], R. Nabben [Two-sided bounds on the inverse of diagonally dominant tridiagonal matrices, Linear Algebr. Appl. 287 (1999) 289–305] and R. Peluso, T. Politi [Some improvements for two-sided bounds on the inverse of diagonally dominant tridiagonal matrices, Linear. Algebr. Appl. 330 (2001) 1–14].     

Lower bounds for some matrices,II

In a series of papers, Rhaly [6]-[8] introduced three classes of matrices which are generalizations of the Cesaro Matrix of order 1. In this paper we obtain lower bounds for these classes, under certain restrictions on p.     

New bounds for Perron root of a nonnegative matrix

In this paper, we obtain some new bounds for Perron root of a nonnegative matrix, which are expressed by easily calculated function in element of matrix. These new results generalize and improve the bounds of G. Frobenius [1] and H. Minc [2], and also extend the known results by Liu [6].     

On lower bounds for singular values of matrix sums

It is pointed out by a counterexample that the result on lower bounds for the absolute singular values of sum of matrices given in [1] is not valid. Moreover, in this note a new result is established on such lower bounds.     

矩阵最小奇异值下界的估计

1．引言与记号记号：儿已（：。X。阶复矩阵集合；从利：A的特征值；一（川：A的最小奇异值；A”：A的共轭转置；【I州：绝对向量范数诱导的矩阵范数；。l（A为A的最大奇异值）时，最小奇异值m（人）下界的估计a是一个关键的数．an（A的下界在其他许多领域中都是一个极重要的课题，因而最小奇异值下界的估计一直是普遍关注的问题二［1，2］等仅利用A的元素得到了N（A）下界的简单估计，至今仍被广泛引用，其结果如下：设AE地（q．若【aiiIZ凡（A）且冲i三q（川，d＝1，…，n，则本文试图通过矩阵的分块和H矩阵特性等来讨论。（）的…     

A comparison of some bounds for the nontrivial eigenvalues of stochastic matrices

Summary Some recently published bounds for the nontrivial eigenvalues of stochastic matrices [1, 2, 4, 5] are compared. It is shown that the Deutsch bound [1] is the best of these bounds and is only slightly improved by a bound given in [3].     

非负矩阵最大特征值的新界值

对最大特征值的上下界进行估计是非负矩阵理论的重要部分,借助两个新的矩阵,从而得到一个判定非负矩阵最大特征值范围的界值定理,其结果比有关结论更加精确.     

Some inequalities for commutators and an application to spectral variation. II

Inequalities that compare unitarily invariant norms of A - B and those of AΓ - ΓB and Γ^-1A - B Γ^-1 are obtained, where both A and B are either Hermitian or unitary or normal operators and Γ is a positive definite operator in a complex separable Hilbert space. These inequalities are then applied to derive bounds for spectral variation of diagonalisable matrices. Our new bounds improve substantially previously published bounds.     

The kth lower bases of primitive non-powerful signed digraphs

In [J. Shao, L. You, H. Shan, Bound on the bases of irreducible generalized sign pattern matrices, Linear Algebra Appl. 427 (2007) 285-300], the authors extended the concept of the base from powerful sign pattern matrices to non-powerful irreducible sign pattern matrices. Recently, the kth local bases and the kth upper bases, which are generalizations of the bases, of primitive non-powerful signed digraphs were introduced. In this paper, we introduce a new parameter called the kth lower bases of primitive non-powerful signed digraphs and obtain some bounds for it. For some cases, the bounds we obtain are best possible and the extremal signed digraphs are characterized, respectively. Moreover, we show that there exist “gaps” in the kth lower bases set of primitive non-powerful signed digraphs.