关于Vandermonde矩阵及其行列式的注记

给出Vandermonde矩阵及其行列式的若干应用,揭示它在高等代数和矩阵分析等方面的重要地位.具体来说,运用Vandermonde行列式来计算几个与之相关的行列式,运用线性方程组来证明组合恒等式,给出两个特殊的Vandermonde矩阵的应用,特别是用Schur矩阵给出了樊畿不等式的一个证明,给出了Vandermonde矩阵与Cauchy矩阵的一个恒等式.     

Cramer法则在数值计算中的若干应用

用Cramer法则给出了Lagrange插值公式和Newton插值公式的简洁证明,同时得到了Vandermonde矩阵的逆矩阵的LU分解.     

线性矩阵方程的行列式求解法

本讨论了线性矩阵方程AXB=C（A、B可逆)的用行列式表示的求解公式·并附带指出它是Cramer法则的重要推广。     

广义行列式与Cramer法则

设A是一个n阶方阵,B是一个n×m矩阵,则容易证明:当A可逆时,矩阵方程AX=B有唯一解:X=A~(-1)B。如果m=1,则由此便得到熟知的Cramer法则。因此,以上结论自然可视为Cramer法则的一种推广。文[4]利用k阶子式阵曾给出Cramer法则的另一种推广。本文则定义一种广义行列式,并由此给出Cramer法则的又一种非常自然的     

反循环矩阵的逆矩阵

贵刊1986年第10期刊出“循环矩阵的逆矩阵”。姚存峰作。(以下简称文[1]),看到这个结论使我们很自然地会想到,能否也给出     

Cramer法则的又一种证法

在《高等代数》（和《线性代数》）的教学中,Ｃｒａｍｅｒ法则被安排在“行列式”一章,但其证明方法却很初等,没有充分体现行列式的运算技巧．我们在教学中对Ｃｒａｍｅｒ法则的证明做了改进,通过构造ｎ＋１阶行列式巧妙地推证出结果,很受学生欢迎．曾见１９８８年《数学通报》１２期发表有该思路的证明方法,故这里称为“又一种证法”．克莱姆法则：如果方程组∑ｎｊ＝１ａｉｊｘｊ＝ｂｉ,ｉ＝１,２,…,ｎ的系数行列式Ｄ＝｜ａｉｊ｜≠０,则方程组有唯一解ｘｊ＝ＤｊＤ（ｊ＝１,２,…,ｎ）．其中,Ｄｊ是将Ｄ中第ｊ列元素换成…     

Cauchy矩阵及其相关的插值问题

用复分析和矩阵方程理论给出C auchy矩阵求逆公式的一种新证明.作为应用,研究与H erm ite-C auchy矩阵相关的N evan linna-P ick插值问题,给出该插值问题全部解的简洁表示.     

Lagrange插值公式与Hermite插值公式的注记

给出一种基于商的形式的Lagrange与Hermite插值公式及其证明,同时还给出了两个相关的不等式.     

关于Mina矩阵及其相关行列式恒等式的一些注释

本文通过对所谓的Mina矩阵$\mathbf{D}^{n}_x(f^{a_k}(x))$建立的LU分解,不仅得到Mina行列式恒等式的一个初等证明,而且还给出了Mina矩阵的逆矩阵. 进一步地,通过建立在拉格朗日插值公式上的矩阵分解,本文给出了Mina型矩阵的两个新的行列式恒等式.     

几种矩阵逆的连续性

非奇异矩阵的逆是矩阵元素的连续函数．学者们也对矩阵广义逆的连续性有所研究．本文应用矩阵分裂和两个矩阵之和的逆的展开式,给出了一般非奇异矩阵,M-矩阵和H-矩阵的逆的连续性．当一些合理的条件满足时,这几种矩阵的逆是连续的．     

Invariants of several matrices

Oblatum 2-XII-1991 & 15-VI-1992     

Notes on Hilbert and Cauchy matrices

Inspired by examples of small Hilbert matrices, the author proves a property of symmetric totally positive Cauchy matrices, called AT-property, and consequences for the Hilbert matrix.     

Notes on some new kinds of pseudoprimes

J. Browkin defined in his recent paper (Math. Comp. 73 (2004), pp. 1031-1037) some new kinds of pseudoprimes, called Sylow -pseudoprimes and elementary Abelian -pseudoprimes. He gave examples of strong pseudoprimes to many bases which are not Sylow -pseudoprime to two bases only, where or .

In this paper, in contrast to Browkin's examples, we give facts and examples which are unfavorable for Browkin's observation to detect compositeness of odd composite numbers. In Section 2, we tabulate and compare counts of numbers in several sets of pseudoprimes and find that most strong pseudoprimes are also Sylow -pseudoprimes to the same bases. In Section 3, we give examples of Sylow -pseudoprimes to the first several prime bases for the first several primes . We especially give an example of a strong pseudoprime to the first six prime bases, which is a Sylow -pseudoprime to the same bases for all . In Section 4, we define to be a -fold Carmichael Sylow pseudoprime, if it is a Sylow -pseudoprime to all bases prime to for all the first smallest odd prime factors of . We find and tabulate all three -fold Carmichael Sylow pseudoprimes . In Section 5, we define a positive odd composite to be a Sylow uniform pseudoprime to bases , or a Syl-upsp for short, if it is a Syl-psp for all the first small prime factors of , where is the number of distinct prime factors of . We find and tabulate all the 17 Syl-upsp's and some Syl-upsp 's . Comparisons of effectiveness of Browkin's observation with Miller tests to detect compositeness of odd composite numbers are given in Section 6.

     

Notes on matrices with diagonally dominant properties

In this paper, we analyze the relation between some classes of matrices with variants of the diagonal dominance property. We establish a sufficient condition for a generalized doubly diagonally dominant matrix to be invertible. Sufficient conditions for a matrix to be strictly generalized diagonally dominant are also presented. We provide a sufficient condition for the invertibility of a cyclically diagonally dominant matrix. These sufficient conditions do not assume the irreducibility of the matrix.     

Stability for several type of interval matrices

The robust stability for some types of tlme-varying interval raatrices and nonlineartime-varying interval matrices is considered and some sufficient conditions for robust stability of such interval matrices are given, The main results of this paper are only related to the verticesset of a interval matrices, and therefore, can be easily applied to test robust stability of interval matrices. Finally, some examples are given to illustrate the results.     

An extension of flanders theorem to several matrices

The Flanders Theorem relates the matrices AB and BA and provides a necessary and sufficient condition for the consistency of the matrix system P = ABQ = BA In this paper, we generalize the Flanders condition for several matrices.     

An extension of flanders theorem to several matrices

The Flanders Theorem relates the matrices AB and BA and provides a necessary and sufficient condition for the consistency of the matrix system P = AB Q = BA In this paper, we generalize the Flanders condition for several matrices.