关于加权差分方法的一点注记

在这篇短文中,对奇异摄动问题引进了新的差分逼近并证明了一致收敛的必要条件。选择适当的权因子可得到用Ilin方法所得的相同的差分格式。     

A Short Note on the Quasilinearization Method for Fractional Differential Equations

Recent literature shows that for certain classes of fractional differential equations the monotone iterative technique fails to guarantee the quadratic convergence of the quasilinearization method. The present work proves the quadratic convergence of the quasilinearization method and the existence and uniqueness of the solution of such a class of fractional differential equations. Our analysis depends upon the classical Kantorovich theorem on Newton's method. Various examples are discussed in order to illustrate our approach.     

差分方程拉克斯对的一种构造性方法

非交换微分在讨论数学物理中的偏微分方程时起着十分重要的作用.最近,作者利用一个具体的非交换外微分建立了一种求差分微分方程拉克斯对的方法,由此检验了该方程的可积性.本文给出了讨论全差分方程的对应理论.另外还讨论了一个格子形变的KdV(LMKdV)方程,并求得了它的拉克斯对.     

关于奇异摄动问题的加权差分方法的注记

本文用例子说明义［１，２］中讨论的关于奇异摄动问题的加权差分格式不是一致收敛的，甚至是不相容的。     

关于随机差分方程的一个注记及其在GARCH模型中的应用

本文对Kesten(1973)中的关_十随机矩阵的更新理论作了一个注记，给出了一个计算尾部指数K1的一个简易方法，并利用此讨论了ARCH(2)和GARCH(2，1)两个时间序列模型的平稳域和分布尾部概率，同时给出一些直观的数值结果。本文结果可看作是对Embrechts et al．(1997)和Mikosch及starica(2000)关于一维随机差分方程应用结果的一个推广．     

The Similarity Method for Difference Equations

In this paper, the similarity method is applied to ordinarydifference equations. When a system of difference equationsadmits symmetries, it follows that the order of equations canbe reduced. Here, by a symmetry is meant a continuous groupwhich leaves the equations invariant. In particular, when aone-dimensional difference equation admits a symmetry, the equationbecomes a linear one and an analytic expression for the solutionmay be obtained. Two examples are given in the final section.     

On the Liapunov Second Method for Difference Equations

We study various kinds of stability of a constant solution of an autonomous difference equation by using auxiliary functions like in the Liapunov Second Method. We establish new general principles and we improve several classical results.     

Sobolev方程基于POD的降阶外推差分算法

用奇异值分解和特征投影分解(proper orthogonal decomposition,简记POD)方法建立Sobolev方程的一种降阶外推有限差分算法,并给出误差估计.最后用数值例子,验证基于POD方法降阶外推有限差分算法的可行性和有效性.     

关于二维Navier-Stokes方程非线性Galerkin校正的注记

本文在对二维Navier-Stokes方程及其近似惯性流形领域估计的基础上，讨论了非线性Galerkin方法校正量的一种可能的最优选取。     

抛物方程基于POD方法的降阶外推差分算法

用奇值分解和特征投影分解(Proper Orthogonal Decomposition,简记POD)方法去建立抛物方程的一种降阶外推有限差分算法,并给出误差估计.最后用数值例子验证这种基于POD方法降阶外推有限差分算法的可行性和有效性.     

含参数线性方程组解的判别方法注记

当线性方程组中含有未知参数时,线性方程组解的情况往往需要进行讨论.本文给出了在非齐次线性方程组系数矩阵中含有未知参数且系数行列式等于零的情况下,判定对应参数值下方程组的解是无解还是有无穷多解的两个判定定理.和以前的方法比较,本文提出的讨论方法更直接.     

A Note on One-Dimensional Stochastic Equations

We consider the stochastic equation

A Variational Complex for Difference Equations

An analogue of the Poincaré lemma for exact forms on a lattice is stated and proved. Using this result as a starting-point, a variational complex for difference equations is constructed and is proved to be locally exact. The proof uses homotopy maps, which enable one to calculate Lagrangians for discrete Euler–Lagrange systems. Furthermore, such maps lead to a systematic technique for deriving conservation laws of a given system of difference equations (whether or not it is an Euler–Lagrange system).     

A Note on Exponential Stability for Evolutionary Equations.

An abstract notion of exponential stability within the framework of evolutionary equations is provided. Sufficient conditions for the exponential stability are given in terms of the so-called material-law operator, which is defined via an operator-valued analytic function. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Method of Difference Potentials for Evolution Equations with Lacunas

Computational Mathematics and Mathematical Physics - A boundary method for computing unsteady wave propagation in three-dimensional space is proposed. The described approach is based on the method...     

常系数非齐次线性差分方程的算子解法

本文利用算子方法 ,解决了常系数非齐次线性差分方程的特解问题 .     

A Note on the LaSalle-Type Theorems for Stochastic Differential Delay Equations

The main aim of this note is to improve some results obtained in the author's earlier paper (1999, J. Math. Anal. Appl.236, 350-369). From the improved result follow some useful criteria on the stochastic asymptotic stability and boundedness.