一类滞后型退化系统的周期解

本文考虑一类滞后型退化高维周期系统B(t)x′(t)=A(t)x(t) f(t,xt),利用线性系统指数型二分性理论和Krasnoselskii不动点定理得到了保证其周期解存在的充分性条件.     

PERIODIC SOLUTIONS OF SCALAR NEUTRAL VOLTERRA INTEGRO-DIFFERENTIAL EQUATIONS WITH INFINITE DELAY

This paper deals with the existence and uniqueness of periodic solutions of the following scalar neutral Volterra integro-differential equation with infinite delaywhere a, C, D, f are continuous functions, also a(t + T) = a(t), C(t + T,s + T) = C(t, s), D(t + T,s + T) = D(t, s), f(t + T) = f(t). Sufficient conditions on the existence and uniqueness of periodic solution to this equation are obtained by the contraction mapping theorem.     

POSITIVE PERIODIC SOLUTION OF AN INTEGRO-DIFFERENTIAL PREDATOR-PREY SYSTEM WITH INFINITE DELAYS

With the help of a continuation theorem based on Gaines and Mawhin's coincidence degree, easily verifiable criteria are established for the global existence of positive periodic solutions of a differential-integral predator-prey system with infinite delaywhere N1(t), N2(t) satisfy N1(t) =φ1(t), N2(t) =φ2(t), φi∈ BC((∞,0],R+φi(0)> 0,i=1,2, ∫0+∞Ki(s)ds = 1, i=1,2,3.     

一类积分微分方程周期解的存在性和唯一性

本文考虑具连续时滞和离散时滞的非线性积分微分方程x'(t)=A(t,x(t))x(t)+∫-∞tC(t,s)x(s)ds+∑i=1i gi(t,x(t—τi(t)))+b(t)和x’(t)=f(t,x(t))+∫-∞tC(t,s)x(s)ds+∑i=1igi(t,x(t-τi(t)))+b(t)周期解的存在性和唯一性问题,这里t∈R,x∈Rn;A(t,x),C(t,s)为n×n阶连续的函数矩阵; f(t,x),gi(t,x)(i=1,2,…,l),b(t)是n维连续向量.通过利用线性系统指数型二分性理论和泛函分析方法研究上述系统,获得了保证其周期解存在性、唯一性的充分性条件.我们除了实质性的推广和改进了已有的结果外,还得到三个新的定理,这是用已有的方法无法获得的(见文[1-30]).     

中立型标量积分微分方程的周期解

本文考虑中立型标量方程x′(t)=a(t)x(t)+∫