任意除环上一矩阵方程组的一般解与中心和反中心对称解

Necessary and sufficient conditions are given for the existence of the general solution, the centrosymmetric solution, and the centroskewsymmetric solution to a system of linear matrix equations over an arbitrary skew field. The representations of such the solutions of the system are also derived.     

多元二次映射的广义稳定性

In this paper we unify the system of functional equations defining multi-quadratic mappings to a single equation, find out the general solution of it and prove its generalized Hyers-Ulam stability.     

On the stability of contact discontinuity for Cauchy problem of compress Navier-Stokes equations with general initial data

In this paper,we study the stability of solutions of the Cauchy problem for 1-D compressible NarvierStokes equations with general initial data.The asymptotic limit of solution is found,under some conditions.The results in this paper imply the case that the limit function of solution as t →∞ is a viscous contact wave in the sense,which approximates the contact discontinuity on any finite-time interval as the heat conduction coefficients toward zero.As a by-product,the decay rates of the solution for the fast diffusion equations are also obtained.The proofs are based on the elementary energy method and the study of asymptotic behavior of the solution to the fast diffusion equation.     

体上一矩阵方程组的再研究

Let F,Qand Q be an arbitrary skew field,a skew field with an involutorial antiautomorphism,a strong p-division ring,respectively.This paper is sequel to [1].A practical method of finding the general solution of the system of matrix equations over F is presented.The necessary and sufficient conditions for the existence of and the explicit expressions for the self-conjugate matrix solution over Q,the positive semidefinite self-conjugate matrix solution over Q of the system are derived.     

A Parameter-Uniform Finite Difference Method for a Coupled System of Convection-Diffusion Two-Point Boundary Value Problems

A system of m (≥2) linear convection-diffusion two-point boundary value problems is examined,where the diffusion term in each equation is multiplied by a small parameterεand the equations are coupled through their convective and reactive terms via matrices B and A respectively.This system is in general singularly perturbed. Unlike the case of a single equation,it does not satisfy a conventional maximum princi- ple.Certain hypotheses are placed on the coupling matrices B and A that ensure exis- tence and uniqueness of a solution to the system and also permit boundary layers in the components of this solution at only one endpoint of the domain;these hypotheses can be regarded as a strong form of diagonal dominance of B.This solution is decomposed into a sum of regular and layer components.Bounds are established on these compo- nents and their derivatives to show explicitly their dependence on the small parameterε.Finally,numerical methods consisting of upwinding on piecewise-uniform Shishkin meshes are proved to yield numerical solutions that are essentially first-order conver- gent,uniformly inε,to the true solution in the discrete maximum norm.Numerical results on Shishkin meshes are presented to support these theoretical bounds.     

PARALLEL SCHWARZ ALGORITHMS FOR PARABOLIC EQUATIONS AND ERROR ESTIMATES

In this paper we introduce two kinds of parallel Schwarz domain decomposition me thods for general, selfadjoint, second order parabolic equations and study the dependence of their convergence rates on parameters of time-step and space-mesh. We prove that the, approximate solution has convergence independent of iteration times at each time-level. And the L~2 error estimates are given.     

矩阵方程组$AX=B,XC=D$的Hermitian自反(反Hermitian自反)最小二乘解及其最佳逼近

In this paper,the Hermitian reflexive（Anti-Hermitian reflexive）least-squares so-lutions of matrix equations（AX = B,XC = D）are considered.With special properties of partitioned matrices and Hermitian reflexive（Anti-Hermitian reflexive）matrices,the general expression of the solution is obtained.Moreover,the related optimal approximation problem to a given matrix over the solution set is considered.     

A TAYLOR APPROXIMATION METHOD OF STOCHASTIC INTEGRO-DIFFERENTIAL EQUATIONS

In this paper, we formulate a general framework of an analytic approximation of the solutions to some It o stochastic integro-differential equations defined on sub-intervals of an arbitrary part of the time-interval [0,1] and connected at successive division points. The integral parts and coefficients of the equation are approximated by their Taylor polynomial which series up to arbitrary derivatives. The suggested approximations converge to the initial solution in the Lp-th norm with some order.     

STABILITY OF GENERAL LINEAR METHODS FOR SYSTEMS OF FUNCTIONAL-DIFFERENTIAL AND FUNCTIONAL EQUATIONS

This paper is concerned with the numerical solution of functional-differential and func-tional equations which include functional-differential equations of neutral type as special cases. The adaptation of general linear methods is considered. It is proved that A-stable general linear methods can inherit the asymptotic stability of underlying linear systems.Some general results of numerical stability are also given.     

THE BOUNDARY VALUE PROBLEMS FOR QUASILINEAR HIGHER ORDER ELLIPTIC EQUATIONS WITH A SMALL PARAMETER

In this paper we deal with the general boundary value problems for quasilinear higherorder elliptic equations with a small parameter before higher derivatives.By using themethod of multiple scales,we have proved that if the solution of degenerated boundary valueproblem exists,then under certain assumptions as the small parameter is sufficiently small,the solution of the origional boundary value problem exists as well and it is unique in a certainfunction space.Besides,the asymptotic expansion of the solution has been constructed.     

CONSISTENCY OF THE FIELD EQUATIONS IN THE SCALE COVARIANT THEORY OF GRAVITATION

ABSTRACT

In the theory of general relativity, it is well known that the integrability conditions for Einstein's field equations are the conservation equations. The latter guarantee that if the constraint equations G^oa = kT^oa hold on an initial surface, and if G^av = kT^av at all times, then the constraint equations will hold at all earlier and later times. This ensures the consistency of the field equations and underlies the initial value approach to their solution. We investigate the corresponding result in the scale co-variant theory of gravitation.     

有理插值(m/n)_f方程组的性质与作用

1引言 记Pn为次数不超过n的一元多项式函数类,约定零多项式的次数为-∞,即deg(0)=一∞;记Rm,n为分子属于Pm,分母属于Pn＼{0}的一元有理函数类.在[1-5]的基础上,文[6]引进了有理插值问题的(m-n)f方程组,其为经典(m/n)f方程组的一种等价变换.由于变换之后,使得参数之间地位相同,并且在个数上也与空间自由度一致,因此成为分析有理插值的一个有力工具.文[7]利用(m-n)f方程组,讨论了有理插值的基本特征,给出并证明了关于基本特征的基本关系定理.文[8]则在此基础上解决了有理插值的适定性问题.     

THE RELATION OF TWO-DIMENSIONAL VISCOUS CAMASSA-HOLM EQUATIONS AND THE NAVIER-STOKES EQUATIONS

In this article, the authors show the existence of global solution of two-dimensional viscous Camassa-Holm (Navier-Stokes-alpha) (NS-α) equations. The authors also prove that the solution of the NS-α equations converges to the solution of the 2D NS equations in the inviscid limit and give the convergence rate of the difference of the solution.     

BLOW-UP SOLUTIONS FOR A CASE OF b-FAMILY EQUATIONS

In this article, we study the blow-up solutions for a case of b-family equations.Using the qualitative theory of differential equations and the bifurcation method of dynamical systems, we obtain five types of blow-up solutions: the hyperbolic blow-up solution, the fractional blow-up solution, the trigonometric blow-up solution, the first elliptic blow-up solution, and the second elliptic blow-up solution. Not only are the expressions of these blow-up solutions given, but also their relationships are discovered. In particular, it is found that two bounded solitary solutions are bifurcated from an elliptic blow-up solution.     

DAE的Runge-Kutta方法在不可压NS方程求解中的应用

1．引言自然界中的流场通常是非定常复杂流场，要正确模拟和跟踪复杂流场的变化，计算格式的时间精度极为重要．对于常微分方程（＊＊q，一般采用＊K方法及线性多步法来提高格式的时间精度．前者是单步法，在计算过程中可以改变步长，可找到稳定性较好的高精度格式：近年来在发展到偏微分方程的数倩水解中也有很多应用．原始变量的INS方程（二维）为：其中u，v分别是x，y方向速度分量，r是压力，连续方程（1．幻可视为约束条件．从［1］，［2］可见，经空间差分化后（固定空间网格），它可看作带约束的微分方程组，即微分代数方程（DAE－…     

高阶代数微分方程解的增长级(英文)

本文研究了高阶代数微分方程解的增长级的问题.利用亚纯函数的Nevanlinna值分布理论和微分方程的一些技巧,得到了一个更精确和更一般的结论,推广了何育赞和Laine的一些理论.     

刚性方程数值方法的危险性问题

为了找出有效地处理Stiff方程的数值方法,Gear给出了数值方法Stiff稳定性的定义,见[1]。根据这个定义,可以找出一些好的数值方法,例如基于数值微分的Gear方法,Enright的一阶导数方法等.但[2]中通过两个具体的例子说明此类方法具有“危险     

BOUNDARY LAYER ESTIMATION OF THE QUASILINEAR STOKES EQUATIONS

1IntroductionConsidertheequationwhereaisaconstantin(0,1).ThesolutionisclearlyWenowomittheviscositytermandaboundaryconditionof(1.1)asfollows:Thesolutionof(1.2)isForesmallandx>E,thetwosolutionsareclosetogether.Theregionwheretheyaredrasticallydifferentisconfinedtotheinterval[0,E],whichisthesthcalledboundarylayer.Notesthatase~0,theboundarylayershrinkstozero,hiltthemaximumdifferencebetweenIReceivedMar.9,1995;revisedSep.18,1996.ThisworkissupportedbyFoundationoflhstituteofMathematics,Acadedasin…     

多变量FUZZY关系方程组解的进一步研究

本文给出一个把多变量ＦＵＺＺＹ关系方程组的求解问题转化为单变量ＦＵＺＺＹ关系方程组来加以解决的方法，这一方法被应用到关于解集结构的研究上，获得了良好的结果。