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。     

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.     

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.     

SUFFICIENT CONDITIONS FOR THE EXISTENCE OF PERIODIC SOLUTIONS OF A AUTONOMOUS DIFFERENTIAL SYSTEM

ＳＵＦＦＩＣＩＥＮＴＣＯＮＤＩＴＩＯＮＳＦＯＲＴＨＥＥＸＩＳＴＥＮＣＥＯＦＰＥＲＩＯＤＩＣＳＯＬＵＴＩＯＮＳＯＦＡＡＵＴＯＮＯＭＯＵＳＤＩＦＦＥＲＥＮＴＩＡＬＳＹＳＴＥＭＨｕａｎｇＬｉｈｏｎｇ（黄立宏）ＹｕＪｉａｎｓｈｅ（庚建设）（Ｄｅｐａｒｔｍｅｎ...     

强迫振动中周期解的存在性

本文主要研究了强迫振动方程：ｘ＋（ｆ（ｘ）＋ｇ（ｘ）ｘ）Ｘ＋ｈ（ｘ）＝ｅ（ｔ）的解的有界性以及周期解的存在性,这里ｆ（ｘ）,ｇ（ｘ）,ｈ（ｘ）在（－∞,＋∞）中连续,ｅ（ｔ）在「０,＋∞）上连续,得到了解的有界性与存在周期解的条件。     

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→+∞).     

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.     

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.     

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.     

EXISTENCE OF POSITIVE PERIODIC SOLUTIONS FOR VOLTERRA INTERGO-DIFFERENTIAL EQUATIONS

1 IntroductionThe purpose of the present paper is to deal with the existence of positive periodic solutionsfor the general Volterra inteRro-differential eouation8where a(t) E C(R,R), f0w a(t)dt > 0, b(t) e C(R,(0,oc)), g E C(R x [0,co),[0,co)), anda(t), b(t), g(t, y) are all w-periodic functions. w > 0 is a constant.The function a(t) is unneces8ary to be po8itive. Since the environment fiuctuates randomlyin bad condition, a(t) may be negative.It is well known that the illtegrDedifferentia…     

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.     

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.     

一类四阶离散哈密顿系统周期解的存在性

本文研究了一类四阶离散哈密顿系统周期解的存在性问题.利用临界点理论中的极大极小方法,通过引入两个不同的控制函数,得到了新的可解性条件,并且利用这些条件得到了新的存在性结果.     

TWO EXISTENCE THEOREMS OF PERIODIC SOLUTIONS FOR DIFFERENTIAL DELAY EQUATIONS

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