一类时滞神经网络差分系统周期解的吸引性

考虑一类 Mc Culloch- Pitts型信号函数的时滞神经网络差分系统周期解的吸引性 ,所得结果改进了文献 [6 ]相关结论。     

EXISTENCE OF ALMOST PERIODIC SOLUTIONS FOR DIFFERENCE SYSTEMS

1IntroductionAsisknown,therehavebeenquiteafewresu1tsontheexistenceofalrilostperiodicsolutionsforordinaryanddelaydifferentialstystems.However,tothebestofourknowledge,therehavenotappearedanycorrespondingresu1tsfOrevenordinarydifferencesystemssofar.Todealwithsuchproblems,wewilldefinethenotionoftheso-calleduni-formlyalmostperiodicsequencesbesidesthealmostsequencesandasymptoti-callyalmostsequences.Thenweprovidethecriteriaandthebasicpropertiesofuniformlyalmostperiodicsequenceswhichareneededinestabl…     

中立型对数种群模型的正周期解存在性

本文利用k-集压缩算子的拓朴度抽象连续定理和某些分析技巧,研究了一类中立型对数种群模型dN/dt=N(t)[r(t)-a(t)lnN(t-σ)-b(t)d/dtlnN(t-r)]的正周期解存在性问题。得到了正周期解存在性的新结果。     

THE EXISTENCE OF POSITIVE PERIODIC SOLUTIONS IN A LOGISTIC DIFFERENCE MODEL WITH A FEEDBACK CONTROL

Consider the following nonautonomous delayed periodic logistic difference model with feedback control termwhich describes the evolution of a single species. The existence of a positive periodic solution is established by using the method of Mawhin's coincidence degree. This work has important significance in both theory and applications.     

EXISTENCE OF MULTIPLE PERIODIC SOLUTIONS TO A SECOND-ORDER NONLINEAR DIFFERENCE SYSTEM

In this paper, by the critical point theory, a sufficient condition for the existence of multiple periodic solutions to a nonlinear second order difference system is obtained. An illustrative example is given. Our results improve and generalize some known ones.     

一类激励-抑制型时滞神经网络模型解的收敛性

本文考虑一类激励-抑制型时滞神经网络模型解的收敛性.利用分析的方法并结合平面系统的几何特性,得出初值φ=(ψ,Ψ)∈R2,在响应区间[a,b]的端点a和b处不振动时,解(z(t),y(t))→(0,0)(t→+∞).     

时滞差分方程周期正解的存在性

本文考虑了一类非线性离散种群模型周期正解的存在性.     

一类中立型泛函微分方程周期解问题

本文利用Fourier级数理论和Mawhin重合度拓展定理研究一类中立型泛函微分方程的周期解存在性问题.在其对应的特征方程具有零特征根的条件下,得到了周期解存在性的新结果.     

一类中立型泛函微分方程周期解问题

本文利用Fourier级数理论和Mawhin重合度拓展定理研究一类中立型泛函微分方程d/dt∫R[dD(s)]x(t+s)+∫R[dL(s)]x(t+s)=[Nx](t)+f(t)的周期解存在性问题.在其对应的特征方程具有零特征根的条件下,得到了周期解存在性的新结果.     

ON THE EXISTENCE OF PERIODIC SOLUTIONS FOR LIENARD SYSTEMS

<正> In this paper we study the existence of periodic solutions for n-dimensional Liénard syste-ms of the formx″+((?)~2F(x))/((?)x~2)x′+grad G(x)=e(t), (1.1)where F∈C~2(R~n,R),G∈C~1(R~n,R),e∈C(R,R~n)and e(t)≡e(t+T)for some con-stant T>0.By((?)~2F(x))/((?)x~2),we denote the Hessian Matrix of F at x.     

一类泛函微分方程周期正解的存在性

本文研究了一类带参数的高维泛函微分程(1.1)的周期正解的存在性.利用一个著名的不动点指标定理,获得了该方程周期正解的存在性、多重性和不存在性.     

EXISTENCE OF POSITIVE PERIODIC SOLUTION FOR A DELAYED PERIODIC PREDATOR-PREY MODEL OF IVLEV TYPE

A periodic coefficients predator-prey system of Ivlev type with both discrete and continuous time delay is investigated. A sufficient condition of the existence of positive periodic solution is established for the system by using the continuation theorem of coincidence degree theory.     

EXISTENCE OF TWO PERIODIC SOLUTIONS TO A RATIO-DEPENDENT PREDATOR-PREY MODEL WITH PREDATOR'S HARVEST

In this paper,we study a non-autonomous ratio-dependent predator-prey model with predator's harvest.By means of the coincidence degree theory,we establish sufficient conditions for the existence of at least two positive periodic solutions of this model.     

中立型对数种群模型正周期解的存在性新结果

运用k-集压缩算子的拓扑度抽象连续定理,研究了如下一类高阶微分方程的周期解存在性问题x(m)(t)= r(t)-a(t)x(t-σ)-b(t)x(m)(t-τ).并将其应用于研究一类中立型对数种群模型dN/dt= N(t) [r(t)-a(t) In N(t-σ-b(t)d/(dt)In N(t-τ)]的正周期解存在性...     

EXISTENCE OF MULTIPLE PERIODIC SOLUTIONS TO THREE-SPECIES DELAYED LOTKA-VOLTERRA MODEL WITH DISPERSION AND HARVESTING

The positive periodic solutions to a three-species delayed Lotka-Volterra model with dispersion and harvesting terms are studied in this paper. By the coincidence degree theory, the sufficient conditions for existence of eight positive periodic solutions to the model are obtained.     

EXISTENCE OF PERIODIC SOLUTIONS FOR 3-D COMPLEX GINZBERG-LANDAU EQUATION

In this paper, the authors consider complex Ginzburg-Landau equation(CGL) in three spatial dimensions ut=ρu+(1+iγ）△u-(1+iμ）|u|^2σu+f,where u is an unknown complex-value function defined in 3+ 1 dimensional space-time R^3+1，△ is a Laplacian in R^3, ρ &gt; 0, γ μ are real parameters, Ω∈R^3 is a bounded domain. By using the method of Galeerkin and Faedo-Schauder fix point theorem we prove the existence of approximate solution uN of the problem. By establishing the uniform boundedness of the norm ||uN|| and the standard compactness arguments, the convergence of the approximate solutions is considered. Moreover, the existence of the periodic solution is obtained.     

EXISTENCE AND STABILITY OF PERIODIC SOLUTIONS OF DELAYED BAM NEURAL NETWORKS WITH PERIODIC COEFFICIENTS

In this paper, we study the BAM neural networks with variable coefficients and delays. By using the Banach fixed point theorem and constructing suitable Lyapunov function, we obtain some sufficient conditions ensuring the existence, uniqueness and global stability of periodic solution. These results are helpful to design global exponential stable BAM networks and periodic oscillatory BAM networks.     

一类非线性中立型时滞微分方程周期解的存在性

本文利用k-集压缩算子拓扑度抽象连续定理和某些分析技巧,研究了非线性中立型时滞微分方程x＇（t)=f(t,x(t-τ）,x＇(t-τ) p(t)周期解的存在性。     

TWO EXISTENCE THEOREMS OF PERIODIC SOLUTIONS FOR DIFFERENTIAL DELAY EQUATIONS

ＴＷＯＥＸＩＳＴＥＮＣＥＴＨＥＯＲＥＭＳＯＦＰＥＲＩＯＤＩＣＳＯＬＵＴＩＯＮＳＦＯＲＤＩＦＦＥＲＥＮＴＩＡＬＤＥＬＡＹＥＱＵＡＴＩＯＮＳ￥ＧＥＷＥＩＧＡＯＡｂｓｔｒａｃｔ：Ｔｈｉｓｐａｐｅｒｃｏｒｒｅｃｔｓａｎｄｉｍｐｒｏｖｅｓｔｗｏｔｈｅｏｒｅｍｓ...     

THE EXISTENCE OF PERIODIC SOLUTIONS AND GLOBAL ATTRACTIVITY OF A CONTINUOUS MODEL OF BOBWHITE QUAIL

The existence of a positive periodic solution foru'(t) =u(t)[α(t)-1+β(t)/1+uk(t-τ(t))], t≥0is established. Some sufficient conditions are obtained for the periodic solution to be globally attractive.