实正定方阵乘积的正定性

本文主要讨论两个实正定方阵乘积的正定性，并给出实正定方阵的乘积仍为正定方阵的充分条件．

与复半正定方阵相关的矩阵分解及其应用

与复数域相对应,从Hermite方阵的对角标准型出发,对复方阵的分解,半正定方阵的复线性组合,极分解进行较为详细的探讨.基此可证明任何两个相似的同阶Hermite方阵一定是酉相似的.

实半正定方阵的标准型

所有ｎ×ｎ半正定实方阵的集合记作ＰＳＤｎ。本文证明了半正定实方阵的合同标准型是唯一的，并给出了两个ｎ×ｎ半正定实方阵合同的一个充分必要条件。

实半正定方阵的性质(英文)

首先给出了有关实半正定方阵的若干性质,然后利用实半正定方阵的合同标准形,定义了合同根、第一对称数、第二对称数和第三对称数,并用它们刻画了实半正定方阵的张量积仍为半正定方阵的充分必要条件。

一个实正定方阵行列式不等式的推广

本文得到一个关于实正定方阵行列式的不等式,它是文[1]中相应定理的指数型推广,同时,由其证明过程简便地得到文[2]中定理。文[1]给出了实正定方阵成亚正定矩阵^([3])的概念:设A(?)R^(t×n),R^t是n维实向量空间,若对任意0≠x(?)R^n,有xAx^T>0 (1)则称A是实正定方阵。记S=1/2(A+A^T),K=1/2(A-A^T),我们有:引理1^([3])设A(?)R^(t×n),则A是实正定方阵的充要条件是S是实正定对称阵。

正定方阵的张量积

给出了正定方阵的合同根概念，并利用它，刻画了多个正定方阵的张量积仍为正定方阵的充要条件．

正定实方阵的Kronecker积

本文首先引进并讨论正定实方阵的广义特征值，进而导出正定实方阵的Ｋｒｏｎｅｃｋｅｒ积仍是正定的充要条件，最后作为应用给出正定实方阵的Ｈａｄａｍａｒｄ积仍是正定的一个充分条件．

矩阵不等式及正定方阵的复合阵

本文在非对称实矩阵正定性意义下，定义了矩阵不等式，并讨论了这种不等式的众多性质，给出了若干新的结果．最后，给出了正定方阵的复合阵仍为正定方阵的充要条件．

关于正定四元数方阵的注记

这篇文章给出了四元数方阵为正定的充要条件，另外还给出了线性方程组 Ａｘ ＝ β的反问题具有正定四元数方阵解的充要条件，以及线性方程组Ａｘ ＝

关于正定实方阵的二个结果

G.R.Johson 引入了芷定实方阵的概念,李炯生给出了正定实方阵的若干结果.本文给出正定实方阵的2个结果.

广义正定矩阵的几个注记

给出了广义正定矩阵与稳定矩阵的关系 ,广义正定矩阵Kronecker积的特征值性质和广义正定矩阵的逆矩阵的性质 .

解实正定线性方程组的交替方向迭代法新格式

在许多适用于解实正定方程组的交替方向迭代法(Alternating Direction Iteration,ADI)的格式中,要求诸方向矩阵之间满足乘法可交换条件.这虽然可提高格式的效率,却也限制了ADI的应用范围.本文提出了一些修改的ADI格式(Revised Alternating Direction Iteration,RADI),免除可交换性的苛求,从而极大地扩充了ADI的应用范围.同时,本文还探讨了提高RADI格式效率的若干措施.

矩阵方程 AX=B 的反问题

给出矩阵方程ＡＸ＝Ｂ的反问题具有正定实方阵解的充要条件以及解的一般形式．

琴生不等式的加强

本文采用Lagrange乘数法获得了琴生不等式的加强形式:设a_i>0(i=1,…,n),如果r>1,那么(sum from a_i)~r≥sum from a_i^r-+(n^r-n)[1/n(sum from a^(-1)]^(-r)、如果o<r<1或r≤log_n(n-(n^2-4))~1/2》/2那么(sum from a_i)~r≤sum from a r/i+(n^r-n)[1/n(sum from a_i^(-1)]^(-r)。由此建立了正定矩阵的行列式的一些推广结果。

SYMMETRIC POSITIVE DEFINITE SOLUTIONS OF MATRIX EQUATIONS (AX,XB)=(C,D) AND AXB=C

The symmetric positive definite solutions of matrix equations (AX,XB)=(C,D) and AXB=C are considered in this paper. Necessary and sufficient conditions for the matrix equations to have symmetric positive definite solutions are derived using the singular value and the generalized singular value decompositions. The expressions for the general symmetric positive definite solutions are given when certain conditions hold.

Minor Self-conjugate and Skewpositive Semidefinite Solutions to a System of Matrix Equations over Skew Fields

Minor self conjugate (msc) and skewpositive semidefinite (ssd) solutions to the system of matrix equations over skew fields [A mn X nn =A mn ,B sn X nn =O sn ] are considered. Necessary and sufficient conditions for the existence of and the expressions for the msc solutions and the ssd solutions are obtained for the system.

T平均不等式及其应用

本文建立了n个正实数(?)的(?)次(?)平均(?)的概念:证明T(?)关于(?)在(?)上单增;并将此结果用于正定矩阵的行列式及加强或推广[1～7]的主结果.

The Necessary and Sufficient Conditions for Two Kinds of Matrix Equtions Having Semipositive Subdefinite Solutions

Finding solutions of matrix equations in given set SR n×n is an active research field. Lots of investigation have done for these cases, where S are the sets of general or symmetric matrices and symmetric positive definite or sysmmetric semiposite definite matrices respectively . Recently, however, attentions are been paying to the situation for S to be the set of general(semi) positive definite matrices(called as semipositive subdefinite matrices below) . In this paper the necessary and sufficient conditions for the following two kinds of matrix equations having semipositive, subdefinite solutions are obtained. General solutions and symmetric solutions of the equations (Ⅰ) and (Ⅱ) have been considered in in detail.

The Metapositive Definite Self－Conjugate Solution of the Matrix Equation AXB＝C over a Skew Field

Let F be the strong p-division ring [4]. This paper is sequel to [1]. Metapositive definite self-conjugate matrix over F is defined and the necessary and sufficient conditions for determining whether a partitioned matrix over F is metapositive definite self-conjugate are given.Moreover,a decomposition of pairwise matrices over F with the same numbers of columns is also presented. Whence some necessary and sufficient conditions for the existence of and the explicit expression for the metapositive definite self-conjugate solution of the matrix equation AXB=C over F are derived.

Some new bound estimates of the Hermitian positive definite solutions of the nonlinear matrix equation X^s+ A~*X^(-t) A = Q

The range and existence conditions of the Hermitian positive definite solutions of nonlinear matrix equations Xs+A*X-tA=Q are studied, where A is an n×n non-singular complex matrix and Q is an n×n Hermitian positive definite matrix and parameters s,t>0. Based on the matrix geometry theory, relevant matrix inequality and linear algebra technology, according to the different value ranges of the parameters s,t, the existence intervals of the Hermitian positive definite solution and the necessary conditions for equation solvability are presented, respectively. Comparing the existing correlation results, the proposed upper and lower bounds of the Hermitian positive definite solution are more accurate and applicable.