COMPUTING THE NEAREST BISYMMETRIC POSITIVE SEMIDEFINITE MATRIX UNDER THE SPECTRAL RESTRICTION

Let A and C denote real n × n matrices. Given real n-vectors x1, ... ,xm, m ≤ n, and a set of numbers L = {λ1,λ2,... ,λm}. We describe (I) the set (?) of all real n × n bisymmetric positive seidefinite matrices A such that Axi is the "best" approximate to λixi, i = 1,2,...,m in Frobenius norm and (II) the Y in set (?) which minimize Frobenius norm of ||C - Y||.An existence theorem of the solutions for Problem I and Problem II is given and the general expression of solutions for Problem I is derived. Some sufficient conditions under which Problem I and Problem II have an explicit solution is provided. A numerical algorithm of the solution for Problem II has been presented.     

THE NUMERICAL STABILITY OF THE BLOCK θ-METHODS FOR DELAY DIFFERENTIAL EQUATIONS

This paper focuses on the numerical stability of the block θ-methods adapted to differential equations with a dday argument. For the block θ-methods, an interpolation procedure is introduced which leads to the mumerical processes that satisfy an important asymptotic stability condition related to the class of test problems y＇ (t)=ay(t)+by(t-r) with a,b∈C, Re(a)＜- ｜b｜ and τ>0. We prove that the block θ-method is GP-stable if and only if the method is A-stable for ordinary differential equations. Furthermore, it is proved that the P-and GP-stability are equivalent for the block θ-method.     

ON CONDITIONS FOR THE NON LOCALLY CONVEX LINEAR TOPOLOGICAL SPACE TO HAVE THE H.-B. EXTENSION PROPERTY

In this paper, the conditions for the non lcally convex topological vector space to have the H,-B. extension property is discussed, and the following three results are proved; (1)A closed subspace E0 of a linear topological space E to have the H.-B. property if and only if for every closed hyperplane of E0 is weakly closed, (2) A locally bounded linear topological space (E,τo)to have the H.-B extension property if and only if for every closed subspace E0 of E, the weak topology σ(E0,E^*0)属于τ1|E0, where τ1 is the finest locally convex topology on E which is coarser then τ0. (3)Let E be separated and let E be the completion of E. If every closed subspace E0 of E is the complete hull of E0∩E,then E has H.-B. extension property if and only if E has H.-B. extension property.     

THE PRIMAL—DUAL POTENTIAL REDUCTION ALGORITHM FOR POSITIVE SEMI—DEFINITE PROGRAMMING

In this paper we introduce a primal-dual potential reduction algorithm for positive semi-definite programming. Using the symetric preserving scalings for both primal and dual interior matrices, we can construct an algorithm which is very similar to the primal-dual potential reduction algorithm of Huang and Kortanek [6] for linear programming. The complexity of the algorithm is either O(nlog(X0 · S0/ε) or O(nlog(X0· S0/ε) depends on the value of ρ in the primal-dual potential function, where X0 and S0 is the initial interior matrices of the positive semi-definite programming.     

ALMOST GLOBAL EXISTENCE OF DIRICHLETINITIAL-BOUNDARY VALUE PROBLEM FORNONLINEAR ELASTODYNAMIC SYSTEMOUTSIDE A STAR-SHAPED DOMAIN

This paper deals with the mixed initial-boundary value problem of Dirichlet type for the nonlinear elastodynamic system outside a star-shaped domain. The almost global existence of solution with small initial data to this problem is proved and a lower bound for the lifespan of solutions is given.     

THE RISK MODEL OF THE EXPECTED DISCOUNTED PENALTY FUNCTION WITH CONSTANT INTEREST FORCE

In this article, the expected discounted penalty functionΦδ,α(u) with constant interest 5 and "discounted factor" exp(-αTδ) is considered. As a result, the integral equation ofΦδ,α(u) is derived and an exact solution forΦδ,α(0) is found. The relation between the joint density of the surplus immediately prior to ruin, and the deficit at ruin and the density of the surplus immediately prior to ruin is then obtained based on analytical methods.     

ON THE SHARP GROWTH, COVERING THEOREMS FOR NORMALIZED BIHOLOMORPHIC MAPPINGS IN C^n

In this article.a normalized biholomorphic mapping f defined on bounded starlike circular domain in C″is considered,where z=0 is a zero of order k 1 of f(z)(?) The sharp growth.covering theorems for almost starlike mappings of order a and starlile mappings of order wave established.Meanwhile,the construction of the above mappings on bounded starlike circular domain in C~n is also discussed,it provides the extremal mappings for the growth,covering theorems of the above mappings.     

NUMERICAL ANALYSIS OF THE DYNAMICAL BEHAVIOR OF THE EQUATION OF J-J TYPE

In this paper, we have analysed the dynamical behavior of the Josephson Junction equation bynumerical computation and the theory of dynamical systems. As 0<β<2:1 ε, and ρis not sufficientlylarge, we observed the intermittent chaotic behavior and the period-doubling chaotic behavior in whichpeople are very interested recently. This implies the for some β(0<β<2:1 ε), the dynamicalbehavior of the J-J equation is rather complex.     

A COLLOCATION METHOD FOR THE CONDUCTIVITY PROBLEM WITH DISCONTINUOUS COEFFICIENT

In this paper, a new collocation BEM for the Robin boundary value problem of the conductivity equation ▽(γ▽u) = 0 is discussed, where the 7 is a piecewise constant function. By the integral representation formula of the solution of the conductivity equation on the boundary and interface, the boundary integral equations are obtained. We discuss the properties of these integral equations and propose a collocation method for solving these boundary integral equations. Both the theoretical analysis and the error analysis are presented and a numerical example is given.     

THE PARSEVAL FORMULA IN THE HARMONIC ANALYSIS FOR OPERATOR AND THE SUPPORT FOR OPERATORS

In this paper a harmonic analysis for operators on a homogeneous Banach space on the additional group of real numbers is discussed. Main resu lts are as following:1. The Parseval formula for integrable operators with respect right translation holds under some conditions; i.e., the Fourier transform for the product of opreator T and T~* at zero is equal to the integral for the product of Fourier transform (γ) and (γ)~* in the strong operator topelogy.2. The finite support and finite cosupport for any beunded linear operator are both unique except the having Haar measure zero.3. The following are equivalent: (1) The measurable set M is the supporting set for operator T; (2). The measursble set M is the cosupporting set for T~*.     

一类矩阵的AOR迭代收敛性分析及其与SOR迭代的比较

1 引言 许多实际问题最后常归结为解一个或一些矩阵的线性代数方程组Ax=b （1.1）这里讨论A为（1，1）相容次序矩阵的情形。     

半序集的碰撞数与分层深度贪婪算法

设Ｐ＝（Ｘ，≤）是一个半序集，本文在关于碰撞数的深度贪婪算法的基础上，直接证明了对任意的Ｐ存在一个最优的ＤＬＧ扩张，给出了ＤＬＧ半序集的定义，并证明了半序集Ｐ是ＤＬＧ半序集的一个充分条件，最后给出了ＤＬＧ扩张算法。     

非齐次空间上的奇异积分交换子的有界性

本文在非齐次空间上给出了交换子[b,T](f)=bTf(x)-T(bf)(x)在b(x)是Lipschitz函数时的 Lp(p>1)有界性.     

关于“停走”生成器概率模型中的符合率问题

本文首先建立了“停走”生成器辅出序列的概率模型,给出了“停走”生成器输出序列与其线性移位寄存器序列之间的符合率的计算公式。     

双模范畴间同构态射的构造

本文研究了双模范畴上的同构态射.利用代数上常用的构造方法,给出了模范畴R(C:T)和L(C:T)的定义及双模范畴TMC和TMCM之间的同构映射和证明过程,将代数上双模范畴的一些重要结论进行了推广.     

经济最优化意义下消耗系数的调整

本文基于“正特片矢量法”,提出了一种在经济最优化意义下调整消耗系数的方法.该方法能够综合考虑产综和价格对消耗系数的影响,有着较好的普适性,在计算上简便易行、效果良好,且具有明显的经济意义.     

非齐次空间上的奇异积分交换子的有界性

本文在非齐次空间上给出了交换子[b,T](f)=bTf(x)-T(bf)(x)在b(x)是Lipschitz函数时的Lp(p＞1)有界性.     

THE SOLUTION TO THE SK-MODEL

IIntroductlonAs one ofwell－kn。mean ield models for spin glasses,the SK(Sherrin红on－Kirkpatri山)model has been studied by many authors恤叫2]nd[81,andthe references therein)．Particu－larl儿丁劝a以andls]repm眈* some quite lmerestingresults on It in his one－hour Invited talk tthe International Congress ofMathem航icians held t Berlin in August,ig98．In mathematical terms;the SK－Model Is the study of a cert。n random measure on Z。:＝{一1;1}”for a natural。mber N．Z。Is called configu…     

三项指数和四次均值的精确计算公式(2)

本文进一步深入研究了三项指数和四次均值的计算问题.运用指数和的相关性质并结合求解同余方程组的方法与技巧,利用两种不同的方法获得了两个精确的均值计算公式,揭示了三项指数和的计算与同余方程组解的个数之间的本质联系,推广了已有的结果.     

用离散纵标法计算平板几何反应堆厚度临界尺度的合理性~

自从1944年 chandrasekhar 在辐射迁移现象计算中使用离散纵标法之后,该方法在核反应堆实际计算中有了广泛的应用,因而引起了许多数学工作者的关心.他们去研究和证明该方法的合理性,并已得到很多结果(如[2—10]).本文的目的是证明用离散纵标法计算平板几何反应堆关于厚度的临界尺度本征值的合理性.这里我们讨论介质体