COMPLEX SYMMETRIC TOEPLITZ OPERATORS ON THE UNIT POLYDISK AND THE UNIT BALL

In this article, we study complex symmetric Toeplitz operators on the Bergman space and the pluriharmonic Bergman space in several variables. Surprisingly, the necessary and sufficient conditions for Toeplitz operators to be complex symmetric on these two spaces with certain conjugations are just the same. Also, some interesting symmetry properties of complex symmetric Toeplitz operators are obtained.     

Lienard系统的同宿轨族与闭轨族

本文讨论Ｌｉｅｎａｒｄ系统解的一些定性性质，得到了存在同宿轨族、闭轨族、双曲扇形和椭圆扇形、正负半轨有界及其与等倾线相交的充要条件或充分条件．     

A class of logarithmically completely monotonic functions associated with the gamma function

In this article, a necessary condition, several sufficient conditions and a sufficient and necessary condition for a class of functions involving the gamma function to be logarithmically completely monotonic are established, and then some known results are extended.     

平面自治系统同宿轨族的存在唯一性

本文研究一般平面自治系统     

态射的广义Moore—Penrose逆

本文定义了态射的广义Ｍｏｏｒｅ－Ｐｅｎｒｏｓｅ逆，给出了它存在的一些充要条件，确定了它的一些表达式，推广了关于态射的Ｍｏｏｒｅ－Ｐｅｎｒｏｓｅ逆的相应结果。     

半平面上有限级Dirichlet级数的正规增长

本文在一般的指数条件下,研究了右半平面上有限级Ｄｉｒｉｃｈｌｅｔ级数的增长性和正规增长性与它的系数的关系,得到了两个充要条件．     

THE UNCONDITIONAL STABILITY FOR THE HYPERNEUTRAL TYPE CONSTANT LINEAR CONTROL SYSTEM WITH DELAYS

With great developments of 8cience and technology exten8ion of system scale and variousapplication of computer, control 8ystem become expansive and sophisticated in the structureproperty About the stable questions of the delny type and the delay neutral type continuouscontrol sy8tem, many good result8 bave been establi8hed by many authors, but we seldom 8eethe studying of the unconditional stability problem for the hyperneutral type. In this paper,applying to the frequency domain method and th…     

矩阵方程X+A*X-nA=I的正定解

In this paper we give some sufficient conditions and some necessary conditions under which the matrix equation X A^*X^-nA=I has a positive definite solution. An iterative method which converges to a positive definite solution of this equation is constructed. And an error estimate formula on this iterative method is also derived.     

关于幂等元之差的可逆性

本文研究在一个有单位元的环中两个幂等元之差的可逆性问题,利用幂等元的性质,得到了两个幂等元之差可逆的几个充分必要条件,并给出了在矩阵环中的几个应用.     

广义幂级数环的本质理想和非奇异性

本文研究了广义幂级数环与其系数环在本质理想和非奇异性上的关系.利用本质理想的定义和性质,得到了广义幂级数环的左理想为本质左理想的菪干充分必要条件.在此基础上,给出了广义幂级数环为左非奇异环的充分必要条件.     

幂级数系数重排使型不变的必要条件

根据幂级数系数重排级不变的充要条件，对比研究了幂级数系数的重排与此级数的和函数的型之间的关系，得到了幂级数系数重排型不变的一些必要条件。     

Lattice-ordered triangular matrix algebras

In this article we give some necessary and sufficient conditions for a lattice-ordered semigroup algebra to be isomorphic to a lattice-ordered triangular matrix algebra.     

THE NECESSARV AND SUFFICIENT CONDITIONS FOR LIPSCHITZ LOCAL HOMEOMORPHISM

For a locally Lipschitz map f:$R^{n}\rightarrow R^{n}$,the well known inverse functin theorem gives a sufficient condition for f to be a Lipschitz local homeomorphims at a point $x_{0}$,that is,$\partial f(x_{0}$ is invertible.In this paper,it is showed that this condition is not necessary and some necessary and sufficient conditions are given.     

求解混合型Lyapunov矩阵方程的参数迭代法

采用参数迭代法求一类混合型Lyapunov矩阵方程A~TX XA B~TXB=C的对称解.在方程相容的条件下,给出了迭代法收敛的充要条件和一些充分条件,以及参数的选取方法.最后,利用数值算例对有关结果进行了验证.     

广义严格对角占优矩阵的判定准则

本文给出了广义严格对角占优矩阵的若干充分条件和必要条件,从而改进和推广了一些已有的结果。     

关于代数特征值反问题有解的充分条件

关于代数特征值反问题有解的充分条件张玉诲，朱本仁（山东大学数学系）ＯＮＴＨＥＳＵＦＦＩＣＩＥＮＴＣＯＮＤＩＴＩＯＮＳＦＯＲＴＨＥＳＯＬＶＡＢＩＬＩＴＹＯＦＧＥＮＥＲＡＬＡＬＧＥＢＲＡＩＣＩＮＶＥＲＳＥＥＩＧＥＮＶＡＬＵＥＰＲＯＢＬＥＭＳ￥ＺｈａｎｇＹ...     

全平面上解析的零级Laplace-Stieltjes变换

本文研究了Laplace-Stieltjes变换所定义的零级整函数的增长性.利用型函数,得到了这类整函数关于增长性及正规增长性的充要条件,推广了Dirichlet级数的相关结论.     

可交换随机变量序列的完全收敛性

本文探讨了可交换随机变量的完全收敛性问题，从充性和必要性两方面都作了研究，并把ｉ．ｉ．ｄ．情形下的部分结果作了为特例推出。     

线性空间中代数广义逆的最简表示

本文主要在一般线性空间框架中从纯代数的角度研究代数广义逆的可加性与表示问题.首先在线性空间中利用空间代数直和分解给出I+AT~+可逆的充要条件,进而T~+=T~+(I+A~T+)~(-1),给出了T~+具有最简表示的一系列充要条件.其次讨论了在Banach空间广义逆和Hilbert空间Moore-Penrose逆扰动问题研究中的应用.本文的主要结果推广和改进了相关文献中的一些近期成果.     

EXISTENCE OF SOLUTIONS IN THE FUTURE FOR A CLASS OF NONLINEAR DIFFERENTIAL SYSTEMS

1 IntroductionThe problem cited in the title above is an old problem, and has been studiedby many authors. Some good results can be found in [1-5] and referencesquoted therein.In this paper we are concerned with this problem for the nonlinear differential systemJ 1 -- ':)>.--,,<,> ~ F(x), (1 l)where E,P, F, q and g are continuous real functions defined on R. Clearly, ifputting E(z) = z, p(y) = y and q(y) H 1, then (1.1) gives the well-knownLi6nard system{ 1:,.:<">, (l 2)Therefore, (1.1) is…