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1.
We use the method of averaging and the discrete analogue of Levinson's theorem to construct the asymptotics for solutions of the difference Schrödinger equation. Moreover, we present the general form for the averaging change of variable.  相似文献   

2.
本文研究了,具有分布滞量的非线性中立型抛物方程(E)解的振动性与渐近性,我们的结果推广了Bainov和Petrov[1]对方程的一些结果。  相似文献   

3.
    
The paper discusses the notion of a delay dynamic equation on time scales and describes some asymptotic properties of its solutions. The application of the derived results to continuous and discrete time scales presents new qualitative results for delay differential and difference equations. In particular, our approach faciliates the joint investigation of stability properties of the exact equations and their numerical discretizations.  相似文献   

4.
    
A system of linear differential equations with oscillatory decreasing coefficients is considered. The coefficients have the formt a(t), α > 0 wherea(t) is a trigonometric polynomial with an arbitrary set of frequencies. The asymptotic behavior of the solutions of this system ast → ∞ is studied. We construct an invertible (for sufficiently larget) change of variables that takes the original system to a system not containing oscillatory coefficients in its principal part. The study of the asymptotic behavior of the solutions of the transformed system is a simpler problem. As an example, the following equation is considered:
, where λ andα, 0 <α ≤ 1, are real numbers. Translated fromMatematicheskie Zametki, Vol. 64, No. 5, pp. 658–666, November, 1998.  相似文献   

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The objective of this note is to present new Hille and Nehari type asymptotic criteria for a class of third-order delay dynamic equations on a time scale. Assumptions in our theorems are less restrictive, whereas the proofs are significantly simpler compared to those reported in the literature. The results obtained extend and improve some previous results.  相似文献   

7.
A family of discrete delay advection–reaction operators is introduced along with an infinite matrix formulation in order to investigate the asymptotic behaviour of the orbits of their iterates. The infinite matrices obtained are triangular matrices with only one non-zero subdiagonal. We show that the elements of powers of these matrices can be written as distinctive products of two factors, one of them involving derivatives of the Lagrange polynomials of basic functions with the diagonal elements as nodes. The other factor consists of products of the subdiagonal elements. Consequently the convergence of the iterates of the operators depends on their eigenvalues and the products of their subdiagonal elements.  相似文献   

8.
The integrable discrete hungry Lotka–Volterra (dhLV) system is easily transformed to the qd-type dhLV system, which resembles the recursion formula of the qd algorithm for computing matrix eigenvalues. Some of the qd-type dhLV variables play a role for assisting the time evolution of the others. This property does not appear in the original dhLV system. In this article, we first show the existence of a centre manifold for the qd-type dhLV system. With the help of the centre manifold theory, we next investigate the local convergence of the qd-type dhLV system, and then clarify the monotonicity related to the qd-type dhLV variables at the final phase of the convergence.  相似文献   

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In this paper, we are concerned with stroboscopic averaging for highly oscillatory evolution equations posed in a Banach space. Using Taylor expansion, we construct a non‐oscillatory high‐order system whose solution remains exponentially close to the exact one over a long time. We then apply this result to the nonlinear wave equation in one dimension. We present the stroboscopic averaging method, which is a numerical method introduced by Chartier, Murua and Sanz‐Serna, and apply it to our problem. Finally, we conclude by presenting the qualitative and quantitative efficiency of this numerical method for some nonlinear wave problem. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

11.
张静  陈目 《大学数学》2011,27(3):124-130
对一类二阶Emden-Fowler型中立型时滞积分方程(a(t)x′(t))′+q<,1>(t)|y(t-σ<,1>)|<'α>sgn x(t-σ<,1>)+g<,2>(t)|y(t-σ<,2>)|<'β>sgn y(t-σ<,2>)=0,利用Riccati技巧和积分平均法,给出了一些判定其解振动的充分判据.这些判据仅...  相似文献   

12.
二阶延迟微分方程θ-方法的TH-稳定性   总被引:2,自引:1,他引:1  
徐阳  赵景军  刘明珠 《计算数学》2004,26(2):189-192
This paper is concerned with the TH-stability of second order delay differential equation. A sufficient condition such that the system is asymptotically stable is derived. Furthermore, a sufficient condition is obtained for the hnear θ-method to be TH-stable. Finally, the plot of stability region for the particular case is presented.  相似文献   

13.
    
This paper is concerned with the study of the stability of Runge-Kutta-Pouzet methods for Volterra integro-differential equations with delays. We are interested in the comparison between the analytical and numerical stability regions. First, we focus on scalar equations with real coefficients. It is proved that all Gauss-Pouzet methods can retain the asymptotic stability of the analytical solution. Then, we consider the multidimensional case. A new stability condition for the stability of the analytical solution is given. Under this condition, the asymptotic stability of Gauss-Pouzet methods is investigated.   相似文献   

14.
针对Marion-Temam型非线性Galerkin方法可行性强烈依赖于最小解题规模的不足,利用时滞惯性流形的新思想,以二维Navier-Stokes方程为例,给出了该类非线性Galerkin方法的一种改进形式,并证明了改进后的方法在保持原方法优越性的同时,其可行性条件得到了很大的改善,从而,给出的是一种可行的高效稳定算法。  相似文献   

15.
In this paper, we investigate the growth/decay rate of solutions of a class of nonlinear Volterra difference equations. Our results can be applied for the case when the characteristic equation of an associated linear difference equation has complex dominant eigenvalue with higher than one multiplicity. Illustrative examples are given for describing the asymptotic behaviour of solutions in a class of linear difference equations and in several discrete nonlinear population models.  相似文献   

16.
This paper is concerned with a delay difference system. Some interesting results are obtained for the asymptotic behaviors of the system. Our theorems improve the corresponding theorems in the relevant literature by removing the restriction of the initial conditions.  相似文献   

17.
    
This study introduces the oscillation of higher order nonlinear dynamic equations with a nonlinear neutral term. The findings are obtained via utilising an integral criterion as well as a comparison theorem with the oscillatory properties of a first-order dynamic equation. We propose novel oscillation criteria that improve, extend and simplify existing ones in the literature. The results are associated with several numerical examples.  相似文献   

18.
利用Str6mberg-Torchinsky分解,给出了Triebel空间FEp.q(Rn,X)上算子值傅里叶乘子的一个充分条件.在rl相似文献   

19.
数值求解延时微分方程的步长准则   总被引:2,自引:0,他引:2  
丛玉豪  匡蛟勋 《计算数学》2001,23(2):139-144
1.引言 用一个数值方法求解下列延时微分方程:其中, f: R × Cd × Cd → Cd为给定函数, U(t)当上> 0时为未知函数,τ> 0为常数延时量,ф(t)∈Cd为已知向量值函数.为了检验一个数值方法的数值稳定性,常用如下试验方程:来观察方法的数值稳定性,这里a,b∈C(C为复数集)为已知常数,ф(t)为给定的连续函数(t≤0). 定义 1[2].延时微分方程(简记为DDES)(3)被称为是渐近稳定的,如果(3)的每一个解U(t)满足 方程(3)的特征方程为: 定义 2[2].一数值方法求解DDES称为…  相似文献   

20.
研究了一类二阶非线性摄动微分方程解的振动性质和渐近性质,建立了两个新的振动性与渐近性定理,推广和改进了已有的一些结果.  相似文献   

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