保持交换环上两类矩阵运算的映射

主要针对交换环上两类矩阵的保持问题进行展开:(1)刻画了交换环上全矩阵空间和上三角形矩阵空间的保持反对合矩阵映射的形式.(2)研究了交换环上n阶上三角形矩阵空间的保持伴随矩阵映射的形式.     

基于某一未定型广义Cartan矩阵的fusion环的构造

利用fusion环的一些性质,基于给定的未定型广义Cartan矩阵,构造了两类fusion环.结果表明这两类fusion环均为类群fusion环.     

线性流形上矩阵方程B^TXB=D的反对称解

该文讨论了两类线性流形上矩阵方程B^TXB=D的反对称解和反对称最佳逼近解存在的条件,给出了通解的一般表达式,同时解决了解对给定矩阵的唯一最佳逼近问题.     

整数环上一类三阶矩阵方程有解的充要条件

给出了整数环上一类三阶矩阵方程有解的充要条件.     

体上的矩阵方程AXA=B

设Ｆ和Ω分别表示一个对合反自同构的体，一个加强Ｐ除环，本文定义了Ω上的亚（半）正定矩阵，给出了矩阵方程ＡＸＡ＾＊＝Ｂ在Ｆ上有（斜）自共轭矩阵解及在Ω上有亚（半）正定矩阵解的充要条件及其解集的显式表示。     

除环上的矩阵方程AXB=D

先建立除环上的矩阵范畴,并证明这个范畴是Ａｂｅｌ范畴,然后利用范畴论中的结论给出除环上矩阵方程ＡＸＢ＝Ｄ有解的条件。     

正则环上矩阵分解

利用幂等矩阵和单边可逆阵,给出了正则环上具有群逆的矩阵结构,并证明了具有奇数特征的单边单位正则环上的矩阵都可分解为两个单边可逆矩阵和形式。     

广义四元数矩阵方程AX-DXB=R

设HF为域F上的广义四元数除环，ChF≠2。本文利用拟线性变换T（X）＝AX－DXB讨论HF上矩阵方程AX－DXB＝R的求解问题，获得了上方程存在（唯一）解的几个充分必要条件，并给出了解的显式公式。     

有限域上一类方程解数的注记

设Fq是含有q个元素的有限域,其中q=pr,r≥1,p是奇素数.研究了有限域Fq上Markoff-Hurwitz类型方程,并给出了当其增广次数矩阵在剩余类环Z/(q-1)Z中可逆时其解数公式的组合证明方法.进一步研究了其推广形式,并得到了此推广形式的方程在特殊条件下的解数公式.     

矩阵方程A^TXB=C的正定和半正定解

给出了矩阵方程Ａ＾ＴＸＢ＝Ｃ在正定和半正定矩阵类中有解的充要条件及解的一般表达式。     

A method of explicit factorization of matrix functions and applications

A method of explicit factorization of matrix functions of second order is proposed. The method consists of reduction of this problem to two scalar barrier problems and a finite system of linear equations. Applications to various classes of singular integral equations and equations with Toeplitz and Hankel matrices are given.     

Positive definite solutions of some matrix equations

In this paper we investigate some existence questions of positive semi-definite solutions for certain classes of matrix equations known as the generalized Lyapunov equations. We present sufficient and necessary conditions for certain equations and only sufficient for others.     

Finding a complete set of solutions or proving unsolvability for certain classes of matrix polynomial equations with commuting coefficients

Two classes of matrix polynomial equations with commuting coefficients are examined. It is shown that the equations in one class have complete sets of solutions, whereas the equations in the other class are unsolvable. A method is given for finding the solution set of an equation in the former class.     

Relationship between spectral and coefficient criteria of mean-square stability for systems of linear stochastic differential and difference equations

We establish the relationship (equivalence) between the spectral and algebraic (coefficient) criteria (the latter is represented in terms of the Sylvester matrix algebraic equation) of mean-square asymptotic stability for three classes of systems of linear equations with varying random perturbations of coefficients, namely, the ltô differential stochastic equations, difference stochastic equations with discrete time, and difference stochastic equations with continuous time.     

Stability of invariant maximal semidefinite subspaces. II. applications: Self-adjoint rational matrix functions,Algebraic Riccati equations

The stability of various factorizations of self-adjoint rational matrix functions and matrix polynomials, as well as of hermitian solutions of symmetric matrix algebraic Riccati equations, is studied. In the first part of this paper results on stability of certain classes of invariant subspaces of a matrix which is self-adjoint in an indefinite inner product were obtained. These results serve as the main tools in the investigation.     

Distribution of the spectrum and representation of solutions of degenerate dynamical systems

We propose algebraic methods for the investigation of the spectrum and structure of solutions of degenerate dynamical systems. These methods are based on the construction and solution of new classes of matrix equations. We prove theorems on the inertia of solutions of the matrix equations, which generalize the well-known properties of the Lyapunov equation. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 7, pp. 930–936, July, 1998.     

On the Explicit Solution of Certain First Order Systems of Partial Differential Equations

We consider two classes of systems of partial differential equations of first order. One consists of generalized Stokes-Beltrami equations $ Aw_z = w^*_z $ , $ \lambda Bw_{\bar z} -w^*_{\bar z} $ with square matrices A and B and a scalar factor u . The other may be written in matrix notation as $ v_{\bar z} = c{\bar v} $ where c denotes a square matrix. This system is known as a Pascali system. Both systems are in close connections to certain systems of second order for which the solutions can be represented using particular differential operators. On the basis of these relations we give the solutions of the first order systems explicitly.     

Stability Analysis of Distributed-Order Hilfer–Prabhakar Systems Based on Inertia Theory

The notion of a distributed-order Hilfer–Prabhakar derivative is introduced, which reduces in special cases to the existing notions of fractional or distributed-order derivatives. The stability of two classes of distributed-order Hilfer–Prabhakar differential equations, which are generalizations of all distributed or fractional differential equations considered previously, is analyzed. Sufficient conditions for the asymptotic stability of these systems are obtained by using properties of generalized Mittag-Leffler functions, the final-value theorem, and the Laplace transform. Stability conditions for such systems are introduced by using a new definition of the inertia of a matrix with respect to the distributed-order Hilfer–Prabhakar derivative.     

Classes of Bianchi equations of third order

On the basis of determining equations written out in terms of Laplace invariants, some classes of Bianchi equations of third order similar to well-known classes of hyperbolic equations with two independent variables are singled out.     

On some classes of fourth-order Bianchi equations with constant ratios of Laplace invariants

On the basis of defining equations written out in terms of Laplace invariants, we single out some classes of fourth-order Bianchi equations similar to the well-known classes of hyperbolic equations with two independent variables admitting Lie algebras of maximum dimension.