ON A PAIR OF NON-ISOMETRIC ISOSPECTRAL DOMAINS WITH FRACTAL BOUNDARIES AND THE WEYL-BERRY CONJECTURE

ＯＮＡＰＡＩＲＯＦＮＯＮＩＳＯＭＥＴＲＩＣＩＳＯＳＰＥＣＴＲＡＬＤＯＭＡＩＮＳＷＩＴＨＦＲＡＣＴＡＬＢＯＵＮＤＡＲＩＥＳＡＮＤＴＨＥＷＥＹＬＢＥＲＲＹＣＯＮＪＥＣＴＵＲＥＳＬＥＥＭＡＮ，Ｂ．Ｄ．ＣＨＥＮＨＵＡＭａｎｕｓｃｒｉｐｔｒｅｃ...     

SINGULAR BOUNDARY PROPERTIES OF HARMONIC FUNCTIONS AND FRACTAL ANALYSIS

ＳＩＮＧＵＬＡＲＢＯＵＮＤＡＲＹＰＲＯＰＥＲＴＩＥＳＯＦＨＡＲＭＯＮＩＣＦＵＮＣＴＩＯＮＳＡＮＤＦＲＡＣＴＡＬＡＮＡＬＹＳＩＳＷＥＮＺＨＩＹＩＮＧＺＨＡＮＧＹＩＰＩＮＧＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＪａｎｕａｒｙ１１，１９９５．Ｒｅｖｉ...     

POSITIVE SOLUTIONS OF NEUTRAL FUNCTIONAL DIFFERENTIAL EQUATIONS

ＰＯＳＩＴＩＶＥＳＯＬＵＴＩＯＮＳＯＦＮＥＵＴＲＡＬＦＵＮＣＴＩＯＮＡＬＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳ￥（黄振勋，高国柱）ＨｕａｎｇＺｈｅｎｘｕｎ（Ｄｅｐｔ．ｏｆＭａｔｈｅｍａｔｉｃｓ，ＦｕｄａｎＵｎｉｖｅｒｓｉｔｙ，Ｓｈａｎｇｈａｉ２０...     

ALMOST PERIODIC SOLUTIONS OF NEUTRAL FUNCTIONAL DIFFERENTIAL EQUATIONS WITH NONAUTONOMOUS OPERATOR

ＡＬＭＯＳＴＰＥＲＩＯＤＩＣＳＯＬＵＴＩＯＮＳＯＦＮＥＵＴＲＡＬＦＵＮＣＴＩＯＮＡＬＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＮＯＮＡＵＴＯＮＯＭＯＵＳＯＰＥＲＡＴＯＲ￥ＹＵＡＮＲＯＮＧ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，Ｂｅｉ...     

GLOBAL STRUCTURE OF THE ORBITS OF A KIND OF N－DIMENSIONAL COMPETITIVE SYSTEMS

ＧＬＯＢＡＬＳＴＲＵＣＴＵＲＥＯＦＴＨＥＯＲＢＩＴＳＯＦＡＫＩＮＤＯＦＮ－ＤＩＭＥＮＳＩＯＮＡＬＣＯＭＰＥＴＩＴＩＶＥＳＹＳＴＥＭＳ￥ＣｈｅｎｇＣｈｕｎ－ｃｈｏｒ，Ｌｉｔｗｉｎ（郑振初）（ＨｏｎｇＫｏｎｇＩｎｓｔｉｔｕｔｅｏｆＥｄｕｃａｔｉｏｎ，香港...     

BANDWIDTH SELECTION IN NONPARAMETRIC SPECTRAL DENSITY ESTIMATION OF THE STATIONARY GAUSSIAN PROCESS

ＢＡＮＤＷＩＤＴＨＳＥＬＥＣＴＩＯＮＩＮＮＯＮＰＡＲＡＭＥＴＲＩＣＳＰＥＣＴＲＡＬＤＥＮＳＩＴＹＥＳＴＩＭＡＴＩＯＮＯＦＴＨＥＳＴＡＴＩＯＮＡＲＹＧＡＵＳＳＩＡＮＰＲＯＣＥＳＳ￥ＹＵＤＡＮ（于丹）（ＩｎｓｔｉｔｕｔｅｏｆＳｙｓｔｅｍｓＳｃｉｅｎｃｅ，...     

BOOTSTRAP MAXIMUM LIKELIHOOD ESTIMATION OF THE PARAMETER IN SPECTRAL DENSITY OF STATIONARY PROCESSES

ＢＯＯＴＳＴＲＡＰ　ＭＡＸＩＭＵＭＬＩＫＥＬＩＨＯＯＤＥＳＴＩＭＡＴＩＯＮＯＦＴＨＥＰＡＲＡＭＥＴＥＲＩＮＳＰＥＣＴＲＡＬＤＥＮＳＩＴＹＯＦＳＴＡＴＩＯＮＡＲＹ　ＰＲＯＣＥＳＳＥＳＹＵＤＡＮ（于丹）（ＩｎｓｔｉｔｕｔｅｏｆＳｙｓｔｅｍｓＳｃｉｅｎｃｅ...     

STABILITY AND ALMOST PERIODIC SOLUTIONS OF FUNCTIONAL DIFFERENTIAL EQUATIONS OF NEUTRAL TYPE

ＳＴＡＢＩＬＩＴＹＡＮＤＡＬＭＯＳＴＰＥＲＩＯＤＩＣＳＯＬＵＴＩＯＮＳＯＦＦＵＮＣＴＩＯＮＡＬＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＯＦＮＥＵＴＲＡＬＴＹＰＥＹｕａｎＲｏｎｇ（袁荣）（ＢｅｉｊｉｎｇＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，北京师范大学，...     

A CHARACTERIZATION OF THE SOLUTIONS OF p－ORDER FEIGENBAUM＇S FUNCTIONAL EQUATION WITH TOPOLOGICAL ENTROPY 0

ＡＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＯＦＴＨＥＳＯＬＵＴＩＯＮＳＯＦｐ－ＯＲＤＥＲＦＥＩＧＥＮＢＡＵＭ＇ＳＦＵＮＣＴＩＯＮＡＬＥＱＵＡＴＩＯＮＷＩＴＨＴＯＰＯＬＯＧＩＣＡＬＥＮＴＲＯＰＹ０（廖公夫）￥ＬｉａｏＧｏｎｇｆｕ（Ｄｅｐｔ．ｏｆＭａｔｈ．，Ｊｉ...     

A NOTE ON THE GLOBAL SOLUTIONS OF A SEMILINEAR REACTION DIFFUSION SYSTEM

ＡＮＯＴＥＯＮＴＨＥＧＬＯＢＡＬＳＯＬＵＴＩＯＮＳＯＦＡＳＥＭＩＬＩＮＥＡＲＲＥＡＣＴＩＯＮＤＩＦＦＵＳＩＯＮＳＹＳＴＥＭ（王明新，吴永辉）￥ＷａｎｇＭｉｎｇｘｉｎ（Ｄｅｐｔ．ｏｆＭａｔｈｅｍａｔｉｃｓＭｅｃｈａｎｉｃｓ，ＳｏｕｔｈｅａｓｔＵｎｉｖ，...     

用元素阶的集合和Sylow子群的正规化子阶的集合刻画奇数维的有限正交单群

本文研究了一类单群的数量刻画问题.运用有限单群分类定理及群的元素阶的素图表示的结构定理,获得了有限群G同构于有限正交单群PΩ2n+1(q)(n≥13),当且仅当群的元素的阶的集合一致和群的Sylow子群的正规化子的阶之集合一致.在某种意义推进施武杰教授的一个猜想.     

九参数广义协调元的收敛性

众知周所,解板弯曲问题的Zienkiewicz不协调三次元只对特殊的单元剖分才收敛.但由于这种元采用单元顶点的函数值及二个一阶导数值作为节点参数,计算简单,总体自由度少,所以相继出现一些对Zienkiewicz元的改进形式,使之对任意剖分均收敛,如拟协调元,TRUNC元,Specht元.对这些元的分析见[7—9].最近龙     

SUPERAPPROXIMATION PROPERTIES OF THE INTERPOLATION OPERATOR OF PROJECTION TYPE AND APPLICATIONS

AbstractSome superapproximation and ultra-approximation properties in function, gradient and two-order derivative approximations are shown for the interpolation operator of projection type on two-dimensional domain. Then, we consider the Ritz projection and Ritz-Volterra projection on finite element spaces, and by means of the superapproximation elementary estimates and Green function methods, derive the superconvergence and ultraconvergence error estimates for both projections, which are also the finite element approximation solutions of the elliptic problems and the Sobolev equations, respectively.     

Stokes问题混合元方法中数值积分的影响

１引言用混合有限元方法求解Ｓｔｏｋｅｓ问题的近似解时,有两点重要事项．其一是众所周知的稳定化条件,这就导致在一阶及二阶格式中引人水泡（ｂｕｂｂｌｅ）函数（参见［１］,［２］,［４］和［６］）．其二是在实际计算中,含有体力密度ｆ的积分,需代之以数值积分,而保持原有的逼近阶不变．值得指出的是。该数值积分与水泡（ｂｕｂｂｌｅ）函数项无关．考虑数值积分下的Ｓｔｏｋｅｓ问题混合元逼近：设给定空间其中,是有界连通的多边形区域．考虑Ｓｔｏｋｅｓ问题混合变分形式：求Ｖ,ｐ　Ｍ,使得其中表示Ｌ２内积．众所周知,（…     

二阶常微分方程初值问题C^0有限元的超收敛

基于在一个单元上的改进的单元正交展开，得到二阶常微分方程C^0有限元Uh的误差表示式，以及节点和单元内部一些特征点上的超收敛结果。     

有限元的u-强超收敛点

For a class of two-point boundary value problems, using projection type interpolation we proved there are κ 1, κ u-ultraconvergence points in each element for k degree finite element solution and its derivative, respectively. The computing formulars are given.     

抛物型积分-微分方程有限元近似的超收敛性质

1　引　　言有限元超收敛性质在有限元方法的研究中占有重要的地位 .利用超收敛性不仅可提高有限元实际计算的精度 ,而且还可得到后验误差估计 .对于椭圆问题有限元超收敛性质的研究目前已有了较丰富的结果 [1 - 3] ,而对于近年来引起广泛关注的发展型积分 -微分方程[4- 6] ,这方面的研究尚不成熟 .本文将研究一维抛物型积分 -微分方程半离散有限元近似的超收敛性质 ,证明了剖分单元上的 Lobatto点、Gauss点和拟 Lobatto点分别是函数、一阶和二阶导数逼近的超收敛点 ;并且在一定条件下证明了强超收敛二择一定理 ;在每个单元上 ,单元中点或…     

ON THE FINITE ELEMENT APPROXIMATION OF SYSTEMS OF REACTION-DIFFUSION EQUATIONS BY p/hp METHODS

We consider the approximation of systems of reaction-diffusion equations, with the finite element method. The highest derivative in each equation is multiplied by a parameter ε∈ （0, 1], and as ε → 0 the solution of the system will contain boundary layers. We extend the analysis of the corresponding scalar problem from [Melenk, IMA J. Numer. Anal. 17（1997）, pp. 577-601], to construct a finite element scheme which includes elements of size O（εp） near the boundary, where p is the degree of the approximating polynomials. We show that, under the assumption of analytic input data, the method yields exponential rates of convergence, independently of ε, when the error is measured in the energy norm associated with the problem. Numerical computations supporting the theory are also presented, which also show that the method yields robust exponential convergence rates when the error in the maximum norm is used.     

双参数Morley有限元多重网格法

1、引言 多重网格方法是求解偏微分方程的高效快速算法,在实际中得到广泛应用．[2][6]中考察了Morley元的多重网格方法,并用于双调和方程问题。     

HIGH ACCURACY ANALYSIS OF THE WILSON ELEMENT

1.IntroductionItiswellknownthatsuperconvergenceestimatesanderrorexpansionsfortheconformingfiniteelementsarewellstudiedinmanypapers.Wereferto[16]forasurveyonvariousresultsofsuperconvergenceandto[10]forafundamentalworkonasymptoticerrorexpansionsandto[1]--[3]forsometechniquesonhighaccuracyanalysis.However,forthenonconformingelements,duetothereducedcontinuityoftrialandtestfunctions,itbecomesmoredifficulttodiscusssuperconvergencepropertiesandrelatedasymptoticerrorexpansions.Naturally,peoplewanttoas…