CONVERGENCE IN MEASURE OF MULTIVARIATE PADE APPROXIMANTS

Convergence conclusions of Pade approximants in the univariate case can be found in various papers.However,resuhs in the multivariate case are few.A.Cuyt seems to be the only one who discusses convergencefor multivariate Pade approximants,she gives in[2]a de Montessus de Bollore type theorem.In this paper,wewill discuss the zero set of a real multivariate polynomial,and present a convergence theorem in measure ofmultivariate Pade approximant.The proof technique used in this paper is quite different from that used in theunivariate case.     

ON THE RATES OF CONVERGENCE IN THE CENTRAL LIMIT THEOREM FOR TWO－PARAMETER MARTINGALE DIFFERENCES

ＯＮＴＨＥＲＡＴＥＳＯＦＣＯＮＶＥＲＧＥＮＣＥＩＮＴＨＥＣＥＮＴＲＡＬＬＩＭＩＴＴＨＥＯＲＥＭＦＯＲＴＷＯ－ＰＡＲＡＭＥＴＥＲＭＡＲＴＩＮＧＡＬＥＤＩＦＦＥＲＥＮＣＥＳ￥（龙红卫）ＬｏｎｇＨｏｎｇｗｅｉ（ＩｎｓｔｉｔｕｔｅｏｆＭａｔｈｅｍａｔｉｃａｌ...     

ON THE SELECTION OF REGRESSION VARIABLES

The methods to minimize AIC or BIC criterion function for selection of regression variablesare considered.The main calculations of some of these methods are completed economically andrecursively.The methods are shown to be of strong consistency or overconsistency to the true model.     

ON THE CONVERGENCE OF THE PADE TABLE

This paper offers a general result on the problem whether there exists an infinitesubsequence of [L/M](z) approximants from the (M+1)-th row of the pade tableconverging to f(z). According to this result one cam get the optimum conclusion (mentionedin the last paragraph).     

ON THE CONVERGENCE OF THE MODIFIED SZASZ-MIRAKJAN OPERATOR

A necessary and sufficient condition of convergence for the modified Szasz-Mirakjan operator is estab-lished.     

ON THE RATE OF POINTWISE CONVERGENCE OF THE DURRMEYER-TYPE OPERATORS

For bounded or some locally bounded functions f measurable on an interval I there is estimated the rate of convergence of the Durrmeyer-type operators Lnf at those points x∈IntI at which the one-sided limits f(x± 0) exist. In the main theorems the Chanturiya's modulus of variation is used.     

ON THE CONVERGENCE OF PARALLEL BFGS METHOD

ＯＮＴＨＥＣＯＮＶＥＲＧＥＮＣＥＯＦＰＡＲＡＬＬＥＬＢＦＧＳＭＥＴＨＯＤＣｈｅｎＺｈｏｎｇＦｅｉＰｕｓｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＷｕｈａｎＵｎｉｖｅｒｓｉｔｙ，Ｗｕｈａｎ４３００７２，Ｃｈｉｎａ．）ＺｈｏｕＹｕｎｃａｉ...     

ON THE CONVERGENCE FOR NULL-ARRAYS OF THE POINT PROCESSES

The purpose of this paper is first to establish a representation of the Laplace transformfor the regular infinitely divisible point processes,and then to give a sufficient and neccesarycondition for convergence of the null-arrays toward a regular infinitely divisible pointprocess.     

ON BOUNDARY VALUE PROBLEMS FOROVERDETERMINED ELLIPTIC SYSTEMS OF TWO COMPLEX VARIABLES

In this paper,based on previous results,the Riemann-Hilbert boundary valueproblems with general forms for overdetermined elliptic equations of first order are consi-dered.The characteristic of modified function space is given.It is proved that there existsa unique solution for modified problem of the problem which we discuss.By the way,itis pointed out that there are great differences between overdetermined elliptic systems andfirst order elliptei systems in the plane.     

ON TWO CONJECTURES OF THE QUADRATIC DIFFERENTIAL SYSTEMS

ＯＮＴＷＯＣＯＮＪＥＣＴＵＲＥＳＯＦＴＨＥＱＵＡＤＲＡＴＩＣＤＩＦＦＥＲＥＮＴＩＡＬＳＹＳＴＥＭＳＺＨＡＮＧＸＩＡＮＧ＊ＡｂｓｔｒａｃｔＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＳｅｐｔｅｍｂｅｒ２９，１９９５．＊ＩｎｓｔｉｔｕｔｅｏｆＭａｔｈｅｍａｔｉｃ...     

平面热传导方程Douglas交替方向隐格式的稳定性与收敛性

1 引言 解抛物方程的交替方向差分方法产生于本世纪五十年代,由于其稳定性好、易编制计算程序,几十年来在科学与工程计算中得到了广泛的应用,最早的交替方向差分格式由Peace- man,D.W.和Rachford,H.H.以及Douglas,J,Jr.和Rachford,H.H.给出,Douglas,J.Jr.于1962年提出了后人称之为Douglas格式的一类交替方向隐格式,其特点是有二阶截断误差而且适用于三维情形.下面简要给出其格式。 考虑平面方形区域上热传导方程 (1.1) (1.2) (1.3)其中Ω=(0,1)×(0,1),为其边界,t为时间变量,以及u_o为已知函数. 令x与y方向网格步长均为h,x_i=ih,y_j=jh,N=1/h为正整数;时间步长为△t,t~n=n△t,记w_(ij)~n=w(x_i,y_j,t~n)以及     

关于随机变量加权和的强收敛性注记

设{X,;n≥1}为独立同分布随机序列,{a_(xi);1≤i≤K_n,↑~∞,n≥1}为权系数序列。本文给出三组sum from i=1 to K_n(a_(ai)X_i→0a.s.充分条件。同时,还讨论加权和的完全收敛性,我们的条件比[3]弱。     

A THEOREM ON THE CONVERGENCE OF SUMS OF INDEPENDENT RANDOM VARIABLES

1 IntroductionThroughout this paperl {X., n 2 1} is assumed to be a sequence of independent randomvariables. Fn denotes the distribution function of the partial surns S. = Z Xk. As is known,k = 1oothe series Z X. is said to be essentially convergent (a.s.) if there exists a sequence of constantsn = 1oo{b., n 2 1} such that Z (X. -- 6.) a.s. converges. When this happens we writeClearlyFn(x) = G.(x -- B.). (l.2)Our problem stems from an old conjecture in Probabilistic Number Theory sugges…     

B-值随机变量序列大数定律的收敛速度

设{X_n:n≥1}是在某可分Banach空间B上取值的独立随机变量序列,S_n=X_1+…+X_n,n≥1,对某00和>1,定义P_n(ε)=P(‖S_n‖/n~(1/p)≥ε)。本文的目的是研究当n→+∞时,P(ε)→0的速度,在Banach空间上推广了Heyde和Rohatgi的结果;同时,本文还讨论了P_n(ε)→0的速度与S_n/n~(1/p)→0 a.s.的关系问题。     

任意B值随机变量序列的强收敛性

本文讨论了任意B值随机变量序列的强收敛性，得到了若干强极限定理和强大数定律，已有的经典的若干结论是本文结果的特例。     

关于在∧-∨复合之下格矩阵的收敛性

本文研究了在复合∧-∨下格矩阵幂序列的收敛性，利用格中∧与∨运算的特性，获得了格矩阵幂序列的一些性质，证明了在∧-∨复合下．任一个几乎非自反格矩阵的幂序列是递减与收敛的．     

特殊半鞅的收敛集

本文讨论特殊半鞅的收敛集，利用随机过程的控制关系和停时技巧，给出了特殊半鞅的收敛集的一般定理，推广和改进了已有的部分结果．     

关于任意随机可积序列的一个强收敛定理

本文研究了可积随机适应序列强收敛定理的问题.利用构造截尾停时以及鞅差序列的方法,获得了一类任意积随机适应序列的强收敛定理,推广了若干已知的结果.     

关于广义Newton法的收敛性问题

本文在较弱的条件下,证明了Ｂ－可微方程组的广义Ｎｅｗｔｏｎ法的局部超线性收敛性,为该算法直接应用于非线性规划问题、变分不等问题以及非线性互补问题等提供了理论依据。最后,本文给出了广义Ｎｅｗｔｏｎ法付之实践的具体策略。数值结果表明,算法是行之有效的。     

HAKOPIAN插值的弱收敛性

1　引　　言在 1 982年 ,Ｈａｋｏｐｉａｎ[1 ]提出了一种新的多元插值 这种插值是Ｋｅｒｇｉｎ插值的一种发展 ( [2 - 4 ]) 王和来 [5]在 1 984年给出了这种插值的余项估计 梁在 [6 ]的基础上于 86年给出了二元Ｈａｋｏｐｉａｎ插值的Ｌａｇｒａｎｇｅ型表达式并对定义于单位圆盘上足够光滑的插值函数给出了它的收敛速度估计 [7] 圆盘上的二元Ｈａｋｏｐｉａｎ插值的导数收敛性在 [8]中进行了讨论 最近 ,在 97年 ,梁和吕 [9]进一步研究了Ｈａｋｏｐｉａｎ插值的积分收敛性 我们在这篇文章中对Ｈａｋｏｐｉａｎ插值的弱收敛性进行了研…