四元数矩阵的特征值与奇异值不等式

关于复矩阵特征值与奇异值不等式的研究,[1]中已有既系统又较深入的综述。四元数矩阵的特征值,自[2]、[3]的工作以来,近三十年中进展甚微,其特征值不等式至今未见论述。近些年来,由于体上矩阵标准形理论研究的进展,谢先生在[5]中定义了体上一类矩阵的特征值,使得这方面的研究又有了新的势头。本文就是在[5]的特征值定义下,对四元数矩阵的特征值与奇异值不等式作些考察,将复矩阵论中著名的特征值Cauchy交错定理,奇异值Thompson交错定理以及惯性律的Ostrowski数量公式推广到四元数体H上。     

非线性特征值问题的二次近似方法

本文研究求解非线性特征值问题的数值方法.基于矩阵值函数的二次近似,将非线性特征值问题转化为二次特征值问题,提出了求解非线性特征值问题的逐次二次近似方法,分析了该方法的收敛性.结合求解二次特征值问题的Arnoldi方法和Jacobi-Davidson方法,给出求解非线性特征值问题的一些二次近似方法.数值结果表明本文所给算法是有效的.     

含空隙的各向同性介质Helmholtz方程扰动问题的传输特征值

传输特征值在反散射唯一性理论中具有十分重要的意义.在含空隙的各向同性非均匀介质折射率扰动下,研究了Helmholtz方程传输特征值的存在性问题.首先,通过构造Neumann-Dirichlet算子,建立传输特征值问题的等价形式.然后,进一步构造特征值函数,将扰动的传输特征值问题转化为算子为零特征值的扰动问题.最后,利用隐函数定理的扰动方法证明传输特征值的存在性.     

矩阵的奇异值与特征值的关系探究及应用

讨论矩阵的奇异值与特征值的关系,并给出奇异值在最优化理论分析中的一个应用.     

矩阵特征值、特征向量的确定

首先对由 A的特征值、特征向量求 A- 1 ,AT,A* ( A的伴随矩阵 )、P- 1 AP以及 A的多项式φ( A)的特征值和特征向量的结论作了个归纳 ;对相反的情形 ,我们给出了部分已有的结果 ,并通过四道例题着重讨论了如何由 φ( A)的特征值来求 A的特征值 .     

用有限元方法求解界面特征值问题

用有限元方法计算椭圆型界面特征值问题,实验数据显示近似特征值的变化规律:界面特征值问题中系数的间断性对协调和非协调Crouzeix-Raviart有限元特征值的收敛性并无影响,而且对协调有限元特征值外推以后得到高精度的解,相应的外推值还提供特征值下界;Crouzeix-Raviart元特征值提供特征值下界,这对一般有界区域如"镂空"型区域也成立.另外,还展示近似特征函数的图形.     

四元数自共轭矩阵和的特征值的不等式

本文将Wietandt关于复自共轭矩阵的特征值和的变分特征以及和的特征值的不等式推广到四元数体上，由此还给出了复自共轭矩阵的主对角元与特征值的优化关系的Schur定理、复矩阵的主对角元的模与奇异值的优化关系的Fan定理在四元数体上的推广.     

边界条件中带有谱参数的不连续Sturm-Liouville算子的特征值问题

本文研究了具有转移条件且边界条件含特征参数的Sturm-Liouville算子L的特征值问题.首先,使用微分算子谱分析经典的方法,得到λ是该边值问题的特征值的充要条件,证明了该边值问题最多有可数个实的特征值、没有有限值的聚点.其次,通过渐近估计证得,所研究的Sturm-Liouville算子L有可数个离散的特征值且下方有界.     

矩阵乘积之Schur补的奇异值估计

0引言矩阵特征值和奇异值的估计,在数值代数、线性系统及控制论、力学等学科中有着十分重要的应用.中外学者获得了许多著名结果,但对Schur补的特征值及奇异值的估计则较困难.我国学者王伯英等得到了矩阵Hadamard之积的Schur补不等式及广义Schur余不等式,刘建州等给出了矩阵乘积的Schur补的奇异值估计.本文改进和推广了文献[2]、[4]和[5]中的一些不等式.     

合同下矩阵特征值与T合同下矩阵奇异值的估计

本文讨论了 *合同下 Hermite矩阵的诸特征值及 T合同下对称矩阵 (实或复 )的诸奇异值的变化情况 ,给出的结果改进了 Sylvester,Ostrowski[1] 等人的相应结果 .另外 ,本文还得到了两 Hermite矩阵乘积的特征值和两复矩阵乘积的奇异值的估计 ,改进并推广了 Sha Huyn[3 ] 、郁易生[4 ] 、周金士[5] 等人的结果     

A Local Parameterization of Orthogonal and Semi-Orthogonal Matrices with Applications

This article describes a local parameterization of orthogonal and semi-orthogonal matrices. The parameterization leads to a unified approach for obtaining the asymptotic joint distributions of estimators of singular-values and -vectors, and of eigen-values and -vectors. The singular- or eigen-values can have arbitrary multiplicities. The approach is illustrated on principal components analyzes, canonical correlation analysis, inter-battery factory analysis, and reduced-rank regression.     

上三角无穷维Hamilton算子特征值的代数指标

无穷维Hamilton算子特征函数系是否完备与其代数指标有关,研究了上三角无穷维Hamilton算子特征值的代数指标问题,基于主对角元的特征值和特征向量的某些性质,得到上三角无穷维Hamilton算子的几何重数和代数重数.     

Rohrströmung mit schwachem Drall

Summary The steady laminar flow at high Reynolds' numbers in a straight tube of circular cross-section is investigated under the condition that swirl is present. Given any axially symmetrical distribution of the rotational velocities, the flow downstream is calculated in the special case that the rotational velocities are small compared to the axial velocity. The problem is reduced to an eigen-value problem of an ordinary linear differential equation of second order, the theory of which is developed in detail. Numerical values for the five lowest eigen-values and the corresponding eigen-functions are given. As an example, the decay of an initially rigid rotation is considered.

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HerrnFr. A. Willers zum siebzigsten Geburtstag     

Standard tensor and its applications in problem of singular values of tensors

In this paper, first we give the definition of standard tensor. Then we clarify the relationship between weakly irreducible tensors and weakly irreducible polynomial maps by the definition of standard tensor. And we prove that the singular values of rectangular tensors are the special cases of the eigen-values of standard tensors related to rectangular tensors. Based on standard tensor, we present a generalized version of the weak Perron-Frobenius Theorem of nonnegative rectangular tensors under weaker conditions. Furthermore, by studying standard tensors, we get some new results of rectangular tensors. Besides, by using the special structure of standard tensors corresponding to nonnegative rectangular tensors, we show that the largest singular value is really geometrically simple under some weaker conditions.     

Strict Monotonicity of Eigenvalues and Unique Continuation

In this paper, we show that the strict mononicity of the eigen-values of an uniformly elliptic operator of second order is equivalent to a unique continuation property.     

Asymptotic solution of one-dimensional spectral boundary-value problems with rapidly varying coefficients: The case of multiple spectra

We suggest a method for the construction of complete asymptotic expansions for eigenvalues and eigen-functions of spectral boundary-value problems for differential equations with rapidly varying coefficients in the case of multiple spectra of the averaged problem. The effect of splitting of multiple eigen-values is illustrated by an example of a special fourth-order problem. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 10, pp. 1399–1408, October, 1998.     

Solution of the partial eigenvalue problem for a regular matrix pencilD(λ) =A − λB

One presents the ALGOL procedures which implement the algorithm for the determination of the group of smallest (greatest) eigenvalues and their corresponding eigenvectors for a matrix pencil where A and B are real square matrices of simple structure. From the initial pencil one constructs a matrix C, whose eigenvalues are taken as the initial approximations to the eigenvalues from the group of the smallest (greatest) eigenvalues of the pencil. The refinement of the eigen-values is performed on the basis of the theory of perturbations. Then one determines the eigen-vectors and one computes the infinite norm of the residual. One gives ALGOL programs and test examples.     

On the eigenvalues of matrices

Summary Let A be an n×n matric with arbitrary complex elements and with eigen-values λ₁, λ₂, ..., λ_n. A method is described for the approximàte determination of max | λ_j | ; characteristical is that prescribing a percentual error the number of elementary operations of the process, necessary to reach such precision, depends only on n and not on the elements of A More general characteristical equations are also considered. To Enrico Bompiani on his scientific Jubilee     

Parametric oscillations of an orthotropic cylindrical shell with an elastic filler I. Formulation of the problem

A linear model of a Timoshenko-type shell with an elastic filler is proposed for solving the problem of the parametric oscillations of the system. A class of operators is derived, which act in a Hilbert space, for which the problem of the determination of a spectrum of eigen-values permits an iterative scheme of solution. Thus, the method for solving problems of parametric oscillations of structures proposed by Bolotin is confirmed.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 3, pp. 470–478, May–June, 1974.     

Eigenvalue Monotonicity for the Ricci-Hamilton Flow

In this short note, we discuss the monotonicity of the eigen-values of the Laplacian operator to the Ricci-Hamilton flow on a compact or a complete non-compact Riemannian manifold. We show that the eigenvalue of the Lapacian operator on a compact domain associated with the evolving Ricci flow is non-decreasing provided the scalar curvature having a non-negative lower bound and Einstein tensor being not too negative. This result will be useful in the study of blow-up models of the Ricci-Hamilton flow. Mathematics Subject Classifications (1991): 53C44 In Memory of S.S. Chern