基于格半群的有限状态自动机的同态

本文研究了格值有限状态自动机(LFSA)的同态和强同态及其性质.利用强同态概念,在格值有限状态自动机的状态集上建立了一种等价关系,得到了格值有限状态自动机的商自动机,证明了商自动机与强同态像自动机同构.     

SOME REMARKS ON SINGULAR DARBOUX TRANSFORMATIONS FOR UNITONS

61. IntroductionHarmonic maPS from memann surfaCes to Lie ~ and synUnetric spaces have re~ much attention recentlyll--6]' An imPOrtant class Of harmonic maPS called unitonsis introduced by Uhlenbedll]. In [2,3], Darboux transformation method is introduced, andthe explicit expreS8ionS for Darboux matrices are used to Obtain new ~ maPS froma knOWn one. By introduced the s~ Darboux trareforlnationS and making use of akind of renormalization Procedure, the authors PreSent a purely algebr…     

ON SOME DISCRETE INEQUALITIES USEFUL IN THE THEORY OF CERTAINPARTIAL FINITE DIFFERENCE EQUATIONS

ＯＮＳＯＭＥＤＩＳＣＲＥＴＥＩＮＥＱＵＡＬＩＴＩＥＳＵＳＥＦＵＬＩＮＴＨＥＴＨＥＯＲＹＯＦＣＥＲＴＡＩＮＰＡＲＴＩＡＬＦＩＮＩＴＥＤＩＦＦＥＲＥＮＣＥＥＱＵＡＴＩＯＮＳＢ．Ｇ．Ｐａｃｈｐａｔｔｅ（ＭａｒａｔｈｗａｄａＵｎｉｖｅｒｓｉｔｙ，Ａｕｒａｎｇ...     

数据变换参数的渐近置信域的曲率表示

该文首次用几何方法研究回归模型中数据变换参数及其子集参数的渐近置信域问题．由于文中讨论的是一般的数据变换多参数的渐近置信域的曲率表示，从而有关结论适用于各种数据变换如著名的Box-Cox变换、带有漂移参数的幂变换等变换中变换参数的渐近置信域的曲率表示．     

有限部分保序变换半群POn的具有某种性质的极大子半群

本文研究了有限链上的部分保序变换半群Pon.通过对其幂等元的分析,获得TPOn的极大正则子半群和极大幂等元生成子半群的结构与分类.     

超可解群的若干充分条件

本文研究了有限群的超可解性问题，利用子群的共轭可换性概念及极小反例法，获得了一个群为超可解的若干充分条件．举例说明了主要结果中的假设条件是不可少的．     

非线性双曲型积分微分方程有限元逼近的误差分析

考虑非线性双曲型积分微分方程半离散有限元格式,得到H^1超收敛和最优阶L^∞和W^1,∞模误差估计,结果丰富了有限元方法的理论。     

范畴中态射集星型序的若干研究

本文证得星型序的乘法性质、遗传性质及其在偏序下态射广义逆的从属性质，并将星序的Hartwig上确界定理推广到带有对合*的正性预加法范畴中．     

铁磁链Landau-Lifshitz方程的显式差分法

正如在研究流体动力学时,Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程起着十分重要的作用一样,在对于非平衡态磁学的研究中,描述连续铁磁体自旋场发展过程的 Ｌａｎｄａｎ－Ｌｉｆｓｈｉｔｚ方程［１］起着十分重要的作用［２］．一九九三年,美国和印度签署了一个大约 ２８０万美元的合作研究计划,在三年的时间里,对Ｌａｎｄａｕ－Ｌｉｆｓｈｉｔｚ铁磁链方程进行研究．在无阻尼的情况下,它为一完全可积的孤立子系统［３,４,５］。很多物理学家研究了它的孤立子解的存在性、逆散射方法以及相互碰撞［３,４,５］．关于解的存在性, Ａｌｏｎ…     

ON A CHAIN OF BUTLER GROUPS

1IntroductionThenotationandtelliluologyusedwillmainlyconformtothatof[5].Werecall11ereafewfundamentalnotions.Inthispaper,groupmeansabeliangroup,qdenotestheadditivegroupOfrationals,ZdenotesthegroupOfintegers.Atypeisanequivalenceclassofheightsequences.IfSisafinitesetoftypestheniuf(S)andsup(S)aretypes,whereinf(S)andsup(S)aregivenbycomponentndninlumsandmaximumsofheightsequencesrepresentingtypesinS.Twotorsionfi'eegroupsAandBarequasi-isolllorphicifthereisfEHorn(A,B)suchthatIisamonomorphismand…     

求解具有混合边界条件的拟线性扩散方程的有限元方法的误差估计问题

在M.F.Wheeler的[5]中,对一类拟线性抛物型方程的F.E.M,进行了颇为深入的理论分析。但是,[5]所考虑的方程,其高阶项的系数,尚有某种局限性,以致不能应用于一般的各向异性问题;对于混合边界的情形,也未加讨论。此外,[5]中所涉及的条件也是较强的,如要求解函数u(x,t)∈c~2(Ω×[0,T])等等。 本文对实践中常常遇到的具有第三混合边界条件的一类拟线性扩散问题的F.E.M,在较[5]为弱的条件下,进行了讨论,把有关拟线性问题的误差估计问题归结为某一线性椭圆边值问题F.E.M的误差估计问题。本文的结果是[1]的推广。     

有限群的Coleman外自同构群是p''-群的一些充分条件

本文研究了有限群G的Coleman外自同构群是p'-群这个问题. 利用Sylow p-子群和同调群的性质,得到了有限群的Coleman外自同构群是p'-群的一些充分条件,其结果与M.Hertweck和W.Kimmerle得到的结果是不同的.     

STRONG CONVERGENCE OF A FULLY DISCRETE FINITE ELEMENT METHOD FOR A CLASS OF SEMILINEAR STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS WITH MULTIPLICATIVE NOISE

This paper develops and analyzes a fully discrete finite element method for a class of semilinear stochastic partial differential equations(SPDEs)with multiplicative noise.The nonlinearity in the diffusion term of the SPDEs is assumed to be globally Lipschitz and the nonlinearity in the drift term is only assumed to satisfy a one-sided Lipschitz condition.These assumptions are the same ones as the cases where numerical methods for general nonlinear stochastic ordinary differential equations(SODEs)under"minimum assumptions"were studied.As a result,the semilinear SPDEs considered in this paper are a direct generalization of these nonlinear SODEs.There are several difficulties which need to be overcome for this generalization.First,obviously the spatial discretization,which does not appear in the SODE case,adds an extra layer of difficulty.It turns out a spatial discretization must be designed to guarantee certain properties for the numerical scheme and its stiffness matrix.In this paper we use a finite element interpolation technique to discretize the nonlinear drift term.Second,in order to prove the strong convergence of the proposed fully discrete finite element method,stability estimates for higher order moments of the H1-seminorm of the numerical solution must be established,which are difficult and delicate.A judicious combination of the properties of the drift and diffusion terms and some nontrivial techniques is used in this paper to achieve the goal.Finally,stability estimates for the second and higher order moments of the L2-norm of the numerical solution are also difficult to obtain due to the fact that the mass matrix may not be diagonally dominant.This is done by utilizing the interpolation theory and the higher moment estimates for the H1-seminorm of the numerical solution.After overcoming these difficulties,it is proved that the proposed fully discrete finite element method is convergent in strong norms with nearly optimal rates of convergence.Numerical experiment results are also presented to validate the theoretical results and to demonstrate the efficiency of the proposed numerical method.     

A COMPLETE ANALYSIS FOR SOME A POSTERIORI ERROR ESTIMATES WITH THE FINITE ELEMENT METHOD OF LINES FOR A NONLINEAR PARABOLIC EQUATION

ABSTRACT

A posteriori error estimates for semidiscrete finite element methods for a nonlinear parabolic initial-boundary value problem are considered. The error estimates are obtained by solving local parabolic or elliptic equations for corrections to the solution on each element. The convergence results improve previous results where unnecessary assumptions are imposed on the approximate solution and the elliptic projection of the exact solution.     

伪双曲型积分-微分方程的H~1-Galerkin混合元法误差估计

<正>1引言考虑如下一类具有Lipschitz连续边界(?)Ω的凸有界区域Ω上的伪双曲型积分微分方程其中Ω(?)R~d,(d=1,2,3)J=(0,T],对于固定的T,0T∞,函数0a_0≤a(x,t)≤     

一类函数空间上偏微分算子有界性和紧性的刻画(英文)

本文研究了一类具有再生核的多复变量函数空间上偏微分算子的有界性和紧性.利用算子理论的方法,获得了偏微分算子是有界的和紧的充分必要条件,推广了文献[1]中的结果.     

A STUDY ON SOME PROBLEMS ON EXISTENCE OF SOLUTIONS FOR NONLINEAR FUNCTIONAL-INTEGRAL EQUATIONS

In this paper, we prove the existence of solutions of some nonlinear functional-integral equation by using a fixed point theorem which satisfy the Darbo condition. The results extend the corresponding ...     

关于任意二值随机序列部分和的增量的若干小偏差定理

利用网微分法研究任意二值随机序列部分和增量的小偏差定理 ,在适当的条件下 ,有 :liminfN N +aNi=N XiaN≥α(c) ,limsupN N +aNi=N XiaN≤β(c)