THE EXISTENCE OF ALMOST PERIODIC SOLUTION TO NONLINEAR DIFFERENTIAL EQUATIONS

Ｃｏｎｓｉｄｅｒｎｏｎｌｉｎｅａｒａｌｍｏｓｔｐｅｒｉｏｄｉｃｄｉｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎｘ＝Ａ（ｔ）ｘ（ｔ）＋ｆ（ｔ，ｘ（ｔ））（１）ａｎｄｉｔｓｈｏｍｏｇｅｎｅｏｕｓｌｉｎｅａｒｄｉｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎｘ（ｔ）＝Ａ（ｔ）ｘ...     

一类结合算子分裂和指数型拟合的奇异摄动问题的一致收敛格式

本文将考虑一类最高阶导数项前含有小参数ε的空间方向为二维的对流—扩散方程的一致精度的差分格式,分三部进行讨论。 1 连续问题 我们考虑下面的对流—扩散方程     

一类高维滞后型泛函微分方程的周期解

本文研究一类滞后型函数分方程的周期解问题，利用指数型二分性和不动点定理，在较广泛的条件下证明了该方程的周期解的存在性及唯一性，推广并改进了文[1-3]的主要结果     

PERIODIC SOLUTION FOR A CLASS OF NEUTRAL HIGHER DIMENSIONAL DIFFERENTIAL SYSTEM WITH DELAY

This paper,using the theory of exponential dichotomy and fixed point theo- rem,discusses the existence of periodic solution for a class of neutral higher dimensional differential system with delay,the result extends and improves the result of paper[6].     

ON THE EXISTENCE OF PERIODIC SOLUTION OF HIGHER ORDER PERIODIC SYSTEM

ＯＮＴＨＥＥＸＩＳＴＥＮＣＥＯＦＰＥＲＩＯＤＩＣＳＯＬＵＴＩＯＮＯＦＨＩＧＨＥＲＯＲＤＥＲＰＥＲＩＯＤＩＣＳＹＳＴＥＭ（王全义）华侨大学，邮编：３６２０１１ＷａｎｇＱｕａｎｙｉ（ＨｕａｑｉａｏＵｎｉｖｅｒｓｉｔｙ）Ａｂｓｔｒａｃｔ：Ｉｎｔｈｉｓｐａｐ...     

一类具分布时滞的Hopfield网络模型的概周期解存在性与稳定性

利用Banach空间压缩不动点定理和微分不等式的分析技巧,研究一类具分布时滞的Hopfield神经网络模型的概周期解的存在性和稳定性。得到了系统存在概周期和全局指数稳定的新的充分条件。所得结果改进和推广了相关文献的结论。     

THE EXISTENCE OF ALMOST PERIODIC SOLUTION FOR CELLULAR NEURAL NETWORKS WITH VARIABLE COEFFICIENTS AND DELAYS

In this paper, we study the problem of almost periodic solution for the cellular neural networks with variable coefficients and delays. By ingeniously importing real parameters di > 0(i = 1,2,…n) which can be adjusted, we establish some sufficient conditions which ensure the neural networks exist a unique almost periodic solution, and all other solutions exponentially converge to such an almost periodic solution.     

时标上具Allee效应的动力学方程的概周期解

本文研究了时标上具Allee效应的可再生资源动力学方程的概周期解的存在性与稳定性.利用线性系统指数二分性与压缩映射不动点定理,得到了方程存在唯一概周期解的充分条件.此外,通过构建适当的Laypunov函数,得到了概周期解是全局指数稳定的充分条件.     

EXPONENTIAL STABILITY AND PERIODIC SOLUTION OF HYBRID BIDIRECTIONAL ASSOCIATIVE MEMORY NEURAL NETWORKS WITH DISCRETE DELAYS

In this paper, we study the existence, uniqueness, and the global exponential stability of the periodic solution and equilibrium of hybrid bidirectional associative memory neural networks with discrete delays. By ingeniously importing real parameters di > 0 (i = 1,2, …, n) which can be adjusted, making use of the Lyapunov functional method and some analysis techniques, some new sufficient conditions are established. Our results generalize and improve the related results in [9]. These conditions can be used both to design globally exponentially stable and periodical oscillatory hybrid bidirectional associative neural networks with discrete delays, and to enlarge the area of designing neural networks. Our work has important significance in related theory and its application.     

THE EXISTENCE OF ALMOST PERIODIC SOLUTION TO A CLASS OF ALMOST PERIODIC DIFFERENTIAL SYSTEM

By means of the fixed point theorem and exponential dichotomy, in this paper we investigate the existence of almost periodic solutions to a class of n-dimensional almost periodic systems, which is more general than the systems in [1-2]. We generalize and improve some results in [3].     

时滞BAM神经网络周期解的存在性和全局指数稳定性

本文利用迭合度理论,通过构造适当的Lyapunov泛函并结合Yang不等式分析技巧,获得了具周期系数的时滞BAM神经网络周期解的存在性和全局指数稳定性的充分条件,这些结果对设计全局指数稳定的BAM神经网络与周期振荡的BAM神经网络具有重要的指导意义.     

某类系统广义指数型E稳定性(英文)

研究某类系统广义指数型 E稳定性 ,推广了文献 [1 ],[2 ]的某些结果 .     

微分方程的指数稳定性

比较系统地研究了It方程解的指数稳定性.给出了随机指数稳定性、指数P-稳定性、几乎必然指数稳定性的比较准则,这些比较准则推广了Nevel’son和Has’minskiǐ的相应结果.     

A remark on trigonometric sums

Summary Let <InlineEquation ID=IE"1"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"2"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"3"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"4"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"5"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"6"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"7"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"8"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"9"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"10"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"11"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"12"><EquationSource Format="TEX"><![CDATA[$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation> S(x,\alpha\mid X_p):=\sum_{\substack{p_1p_2<x\\ p_1<p_2}} X_{p_1}X_{p_2}e^{2\pi i\alpha p_1p_2},\qquad \pi_2(x)=\sum_{\substack{p_1p_2<x\ p_1<p_2}} 1, $$ where $p$, $p_1$, $p_2$ run over the prime numbers. It is proved that $$ \max_{\substack{|X_p|\le 1\\ p}} \frac{{S(x,\alpha,X_p)}}{{\pi_2(x)}} =\Delta(x,\alpha)\to 0\qquad(x\to\infty) $$ for almost all irrational $\alpha$.     

Exponential smoothing — I

Some new insights and results for exponential smoothing with application to forecasting and parameter estimation. Multidimensional exponential smoothing is described by a Kalman filter model with a limiting stationary gain matrix.     

非光滑多目标规划非控解和真有效解

考虑问题(P) (?)其中 f(x)=(f_1(x),…,f_m(x))~T,g(x)=(g_1(x),…,g_l(x))~T,C 是 n 维欧氏空间 E_n中的闭集,f_i(x)(i=1,…,m)和 g_j(x)(j=1,…,l)为在 C 的某个邻域中的 Lipschitz函数,D 为 E_l 中的闭凸锥。记R={x|g(x)∈D,x∈C}。设 A 为 E_m 中的非零凸锥。(?)∈R 称为 f(x)(对 A)的非控解,若不存在 x∈R 使     

Uniform Growth in Groups of Exponential Growth

This is an exposition of examples and classes of finitely-generated groups which have uniform exponential growth. The main examples are non-Abelian free groups, semi-direct products of free Abelian groups with automorphisms having an eigenvalue of modulus distinct from 1, and Golod–Shafarevich infinite finitely-generated p-groups. The classes include groups which virtually have non-Abelian free quotients, nonelementary hyperbolic groups, appropriate free products with amalgamation, HNN-extensions and one-relator groups, as well as soluble groups of exponential growth. Several open problems are formulated.     

The diophantine equation (a n-1)(b n-1)=x 2

Let a and b given unequal positive integers; it is desired to determine the positive integer solutions n and x of the equation of the title. Some special cases have recently been considered, and here some general results and conjectures are presented. This revised version was published online in June 2006 with corrections to the Cover Date.     

Preserving geometric properties of the exponential matrix by block Krylov subspace methods

Given a large square real matrix A and a rectangular tall matrix Q, many application problems require the approximation of the operation . Under certain hypotheses on A, the matrix preserves the orthogonality characteristics of Q; this property is particularly attractive when the associated application problem requires some geometric constraints to be satisfied. For small size problems numerical methods have been devised to approximate while maintaining the structure properties. On the other hand, no algorithm for large A has been derived with similar preservation properties. In this paper we show that an appropriate use of the block Lanczos method allows one to obtain a structure preserving approximation to when A is skew-symmetric or skew-symmetric and Hamiltonian. Moreover, for A Hamiltonian we derive a new variant of the block Lanczos method that again preserves the geometric properties of the exact scheme. Numerical results are reported to support our theoretical findings, with particular attention to the numerical solution of linear dynamical systems by means of structure preserving integrators. AMS subject classification (2000) 65F10, 65F30, 65D30