代数特征值反问题Hermite情形可解的充分条件

１　引言及主要结果 本论文将要讨论如下问题［２,４］： 问题ＨＧ给定ｎ＋１个Ｈｅｒｍｉｔｅ矩阵Ａ＝（ａｉｊ）ｎ×ｎ和Ａｋ＝Ｓ和ｎ个实数　,求个实数ｃ１,…,ｃｎ,使得Ａ（ｃ）＝ ．的特征值为 对于上述问题,有解的充分条件已有许多研究结果,如［２,４,６］．下面将利用Ｂｒｏｕｗｅｒ不动点定理给出新的充分条件． 本文的符号和定义如下： 对任意ｎ阶Ｈｅｒｍｉｔｅ矩阵Ｂ＝（ｂｉｊ）,记Ｂ（０）＝Ｂ－ｄｉａｇ（ｂ１１,ｂ２２,…,ｂｎｎ）,ρ（Ｂ）表示Ｂ的谱半径, ｛λ（Ｂ）｝表示Ｂ的特征值（谱）集合,且设　表…     

关于加法逆特征值问题

１．引言 设Ａ（ｃ）＝（ａｉｊ（ｃ））是ｎ阶实矩阵,其元素ａｉｊ（ｃ）（ｉ,ｊ＝１,…,ｎ）是参变量ｃ＝（Ｃ１,…,ｃｎ）Ｔ的实解析函数,λ１（ｃ）,…,λｎ（Ｃ）是矩阵Ａ（ｃ）的特征值,λ１,…,λｎ是给定的实数,代数特征值反问题［４］就是研究如何求解实的ｃ,使Ａ（ｃ）的特征值为给定的λ１,…,λｎ． 假设给定的ｎ个数λ１,…,λｎ互异,且问题的解存在（解不存在时可考虑某种形式的最小二乘解）,过去的研究一般是直接研究或将问题转化为如下等价的非线性方程组 ｄｅｔ（Ａ（ｃ卜人Ｉ）一０, ｉ＝ １,…,…     

具无界时滞非自治Logistic模型的全局吸引性(英文)

考虑非自治Ｌｏｇｉｓｔｉｃ模型△ｘｎ ＝ ｐｎｘｎ（１ － ｘｎ－ ｋｎλ）,　　ｎ ＝ ０,１,…, （１）其中｛ｐｎ｝ｎ０为非负实数列,｛ｋｎ｝ｎ０为非负整数列且ｌｉｍｎ→∞（ｎ－ ｋｎ）＝ ∞,ｌｉｍ ｓｕｐｎ→∞ ｋｎ＝ ∞,λ为正常数．我们获得了方程（１）的平衡点λ全局吸引的新的充分条件,改进了文［５］的相应结果．     

一类扩展线性规划问题的推广

研究文［１］的扩展线性规划问题的更一般的情形：ｍｉｎｚ＝∑ｎｊ＝１ｃｊ｜ｘｊ｜，ｓ．ｔＡｘ＝ｂ，ｘｊ≥０，ｊ∈Ｉ｛１，２，…，ｎ｝。给出其不扩展单纯形表的单纯形算法。     

高阶等比数列的划分

文［１］研究了（一阶）等比数列的高阶等差划分的问题,证明了等比数列的均匀划分仍为等比数列,一阶等差划分为３阶等比数列,并猜想ｋ阶等差划分为２ｋ＋１阶等比数列．本文证明：定理　ｓ阶等比数列的ｔ阶等差划分数列为ｓｔ＋ｓ＋ｔ阶等比数列．为了阅读方便,我们先简述一下有关概念．设｛ａｎ｝＝｛ａ（０）ｎ｝为任一数列（ａｎ≠０）．记ａ（１）ｎ＝ａ（０）ｎａ（０）ｎ＋１,…,ａ（ｓ）ｎ＝ａ（ｓ－１）ｎ＋１ａ（ｓ－１）ｎ,则｛ａ（ｓ）ｎ｝称为｛ａｎ｝的ｓ阶商数列．若ａ（ｓ）ｎ＝ｑ（非１常数）,对ｎ∈Ｎ均成立,则｛…     

由主子阵和缺损特征对构造Jacobi矩阵

１．引言设ｎ阶Ｊａｃｏｂｉ矩阵为 Ｊａｃｏｂｉ矩阵逆特征值问题的研究在振动工程、结构设计和系统参数识别等领域有重要应用．由主子阵和谱数据构造Ｊａｃｏｂｉ阵Ｊｎ,戴华首次得到ｎ为偶数时有解的充要条件,并给出了一个数值算法 ［１］;［２］对 ｎ为任意正整数时给出了一个新算法,此算法在计算过程中可自动判断解的存在性．由缺损特征对和谱数据构造三对角对称阵,［３］给出了有解的充要条件,本文研究由主子阵和缺损特征对构造Ｊａｃｏｂｉ矩阵,其问题如下： 问题Ａ．给定ｋ阶Ｊａｃｏｂｉ阵又给定和求和阶 Ｊａｃｏｂｉ阵使…     

不可约对称三对角矩阵根的隔离定理的推广

１引言设ｎ×ｎ不可约对称三对角矩阵Ｔｐ,ｑ记它的子阵记Ｔｐ,ｑ的特征多项式ｄｅｔ（λI一Ｔｐ,ｑ）=φｐ,ｑ(λ）·于是φ1.ｎ(λ）＝ｎ（λ）即为Tｎ的特征多项式.所谓根的隔离定理,即为：Ｔ1,ｎ－１或Ｔ２,ｎ的特征值和Ｔｎ的特征值满足参见［１,ｐ．３６］．这是对称三对角矩阵的重要性质,在研究求特征值的二分法和特征值反问题时都有用到．这个定理讲的是Ｔｎ与划去第一行,第一列后的矩阵,或划去第ｎ行,第ｎ列后的矩阵Ｔ２,ｎ或Ｔ１,ｎ－１特征值之间的关系．本文将此关系推广到Ｔｎ划去第ｋ行,第ｋ列ｋ＝１,２,…,…     

厄米特矩阵的迹的几点性质

应用矩阵Ａ＝（ａｉｊ）∈Ｃｎ×ｎ的弗罗伯尼范数ＡＦ和谱范数ＡＳ，研究厄米特矩阵的迹的性质，得到几个结论：Ｔｒ（ＡＢ）＝∑ｎｉ＝１λｉ∑ｎｊ＝１ｔｉｊμｊ（λｉ，μｊ分别为Ａ，Ｂ的特征值，０≤ｔｉｊ≤１，且∑ｎｉ＝１ｔｉｊ＝１，ｊ＝１，２，…，ｎ）；Ｔｒ（ＡＢ）≤Ｔｒ（Ａ）ＢＳ；Ｔｒ（ＡＢ）Ｈ（ＡＢ）］≤Ｔｒ（ＡＨＡ）［ｍａｘ１≤ｉ≤ｎλｉ］２（λｉ是Ｂ的特征值）等．     

A Note on the Difference of Gaussian Measure of Two Balls in Hilbert Spaces

§１．　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　ＬｅｔＨｂｅａｓｅｐａｒａｂｌｅＨｉｌｂｅｒｔｓｐａｃｅ，μｂｅａｓｙｍｍｅｔｒｉｃＧａｕｓｓｉａｎｍｅａｓｕｒｅｏｎＨａｎｄλ１≥λ２≥…０ｂｅｔｈｅｅｉｇｅｎｖａｌｕｅｓｏｆｔｈｅｃｏｖａｒｉａｎｃｅμＴ．ＺａｋｇｉｖｅｓｔｈｅｅｓｔｉｍａｔｅｏｆｔｈｅｄｉｆｆｅｒｅｎｃｅｏｆＧａｕｓｓｉａｎｍｅａｓｕｒｅｏｆｔｗｏｂａｌｌ．μ｛ｘ∈Ｈ：ｙｘｙ≤ｔ｝－μ｛ｘ∈Ｈ：ｙｘ＋ｒｙ≤ｔ｝ｉｎ［１，２］．Ｉｎｔｈｉｓｎｏｔｅｗｅｏｂｔａｉｎａｆｉｎｅｒｅｓｔｉｍａｔ…     

Jacobi多项式零点为结点的Lagrange插值多项式之逼近

对于可微函数ｆ∈Ｃｑ［－１，１］，本文研究以Ｊａｃｏｂｉ多项式Ｊ（α，β）ｎ（ｘ）的零点为结点组之Ｌａｇｒａｎｇｅ插值多项式对ｆ及其导数的同时逼近，证明不等式Ｌ（ｓ）ｎ（ｆ，α，β，ｘ）－ｆ（ｓ）（ｘ）＝Ｏ（１）Δ－ｓｎ（ｘ）Δｑｎ（ｘ）ω（ｆ（ｑ），Δｎ（ｘ））ｌｏｇｎ｛＋（１－ｘ＋ｎ－１）－α－１２ｎ－ｑω（ｆ（ｑ），ｎ－１）｝，在［０，１］上对于ｓ＝０，１，２，…，ｑ一致成立，其中Δｎ（ｘ）＝ｎ－１１－ｘ２＋ｎ－２     

New perturbation bounds and condition numbers for the hyperbolic QR factorization

Using the modified matrix-vector equation approach, the technique of Lyapunov majorant function and the Banach fixed point theorem, we obtain some new rigorous perturbation bounds for R factor of the hyperbolic QR factorization under normwise perturbation. These bounds are always tighter than the one given in the literature. Moreover, the optimal first-order perturbation bounds and the normwise condition numbers for the hyperbolic QR factorization are also presented.     

Mixed,componentwise condition numbers and small sample statistical condition estimation of Sylvester equations

We present a componentwise perturbation analysis for the continuous‐time Sylvester equations. Componentwise, mixed condition numbers and new perturbation bounds are derived for the matrix equations. The small sample statistical method can also be applied for the condition estimation. These condition numbers and perturbation bounds are tested on numerical examples and compared with the normwise condition number. The numerical examples illustrate that the mixed condition number gives sharper bounds than the normwise one. Copyright © 2011 John Wiley & Sons, Ltd.     

Perturbation analysis of singular subspaces and deflating subspaces

Summary. Perturbation expansions for singular subspaces of a matrix and for deflating subspaces of a regular matrix pair are derived by using a technique previously described by the author. The perturbation expansions are then used to derive Fr\'echet derivatives, condition numbers, and th-order perturbation bounds for the subspaces. Vaccaro's result on second-order perturbation expansions for a special class of singular subspaces can be obtained from a general result of this paper. Besides, new perturbation bounds for singular subspaces and deflating subspaces are derived by applying a general theorem on solution of a system of nonlinear equations. The results of this paper reveal an important fact: Each singular subspace and each deflating subspace have individual perturbation bounds and individual condition numbers. Received July 26, 1994     

Bounds and perturbation bounds for the matrix exponential

Some new types of bounds and perturbation bounds, based on the Jordan normal form, for the matrix exponential are derived. These bounds are compared to known bounds, both theoretically and by numerical examples. Some recent results on the matrix exponential and the logarithmic norm are also included.     

On perturbation bounds of the linear complementarity problem

In this paper, new perturbation bounds for linear complementarity problems are presented based on the sign patterns of the solution of the equivalent modulus equations. The new bounds are shown to be the generalization of the existing ones.     

Some New Perturbation Bounds for Subunitary Polar Factors

In this paper, we present some new perturbation bounds for subunitary polar factors in a special unitarily invariant norm called a Q-norm. Some recent results in the Frobenius norm and the spectral norm are extended to the Q-norm on one hand. On the other hand we also present some relative perturbation bounds for subunitary polar factors.     

关于特征值与广义特征值的Bauer-Fike型相对扰动界

本文研究特征值与广义特征值的Bauer-Fike型相对扰动界.我们给出了一些新的结果.这些界从一定的意义上改进了以往相应的结论.     

Hermite矩阵特征值的新扰动界

本文研究了Hermite矩阵特征值的任意扰动,给出了新的绝对和相对扰动界．所给出的界改进了Hoffman-Wielandt和Kahan早期的结果．     

On the perturbation of the Q‐factor of the QR factorization

This paper gives normwise and componentwise perturbation analyses for the Q‐factor of the QR factorization of the matrix A with full column rank when A suffers from an additive perturbation. Rigorous perturbation bounds are derived on the projections of the perturbation of the Q‐factor in the range of A and its orthogonal complement. These bounds overcome a serious shortcoming of the first‐order perturbation bounds in the literature and can be used safely. From these bounds, identical or equivalent first‐order perturbation bounds in the literature can easily be derived. When A is square and nonsingular, tighter and simpler rigorous perturbation bounds on the perturbation of the Q‐factor are presented. Copyright © 2011 John Wiley & Sons, Ltd.     

Relative eigenvalue and singular value perturbations of scaled diagonally dominant matrices

The paper derives improved relative perturbation bounds for the eigenvalues of scaled diagonally dominant Hermitian matrices and new relative perturbation bounds for the singular values of symmetrically scaled diagonally dominant square matrices. The perturbation result for the singular values enlarges the class of well-behaved matrices for accurate computation of the singular values. AMS subject classification (2000)  65F15