带有逐段常数滞后变量的一阶非线性微分方程的周期边值问题

考虑如下一阶非线性微分方程边值问题y′(t)=f(t,y([t-k])),t≥0, (*)y(0)=y(T), (**)这里[·]表示最大取整函数,k 是一个自然数,T>O.本文利用下上解方法获得问题(*)(**)解存在的定理及比较定理。     

一类非齐次迭代泛函微分方程的周期解（英文）

本文利用Krasnoselskii不动点定理考虑了一类非齐次迭代泛函微分方程x'(t)=c_1x(t)+c_2x~([2])(t)+F(t)周期解的存在唯一性问题,推广了迭代泛函微分方程周期解的相关理论.     

一阶非线性中立型泛函微分方程的振动性

近年来,关于一阶线性中立型泛函微分方程的振动性已有不少结果,但对于一阶非线性中立型泛函微分方程的振动性结果迄今很少见到。对下列的中立型泛函微分方程其中:P,τ,σ为正常数,Q(t),h(t)∈C[t_0,+∞),Q(t)>0,f(x)∈C(R,R),当x≠0时,Xf(x)>0。本文建立了振动性的两个结果。     

不动点和一类中立型方程的渐近稳定性

本文用不动点定理研究了一类中立型泛函微分方程[x(t)-P(t)x(t-τ)]′+Q(t)x(t-r(t))=0,t≥t0的零解的渐近稳定性,其中τ∈(0,∞),P,Q∈C([t0,∞),R),r∈C([t0,∞),R+),且当t→∞时t-r(t)→∞.我们讨论了r(t)为常数和不为常数两种情况.所得定理改进和包含了前人已有的结果.     

LINEARIZED OSCILLATIONS OF DELAY DIFFERENTIAL EQUATIONS AND APPLICATIONS

The necessary and sufficient conditions for the oscillations of every solution of the nonlinear delay equation x(t) f(x(t l)) g(x([t-k]))=0 are oblained.     

一类二阶泛函微分方程的振动性质

本文讨论了二阶泛函微分方程[a(t)φ(χ(t))Ψ(χ'(t))]'+Q(t,χ(t),χ(q(t)))=P(tχ(t),χ'(p(t)))的非振动解的性质与分类及解的振动性.     

一阶中立型非线性泛函微分方程解的振动性

一、引言 本文主要考虑下面的一阶中立型非线性泛函微分方程:[x(t)-cx(t-r)]′ sum from t=1 to N p_i(t)f_i(x(τ_i(t)))=0(t≥t_0>0) (1)的解的振动性。 当r=0时,(1)退化成非中立型方程,对该方程已有大量文章进行了讨论,因而我们不再考虑这种情况,而直接假定(1)满足: (i)c≥0,r>0都是常数; (ii)p_i(t)∈C([t_0, ∞),R~ )且不在[t_0, ∞)任何右半区间上恒为零,τ_i(t)∈     

具分片常变量泛函微分方程的全局稳定性

本文研究具分片常变量泛函微分方程,其中[·]表示取整函数,r(t)∈C([0,+c),(0,+c)),P_i∈[0,+c),(i=1,2,…,m),P_m>0,文中给出了保证方程的每一满足初始条件N(0)=N₀>0,N(-j)=N_-j≥0(j=1,2,…,m),的解N(t)满足lim_t→∞N(t)=N^*的一些新的充分条件.     

高阶泛函方程解的非振动准则

研究一类高阶非线性泛函微分方程用x(g(t)=p(x)x(t)+Q(t)multiply from i=1to m|x(gki+1(t))|aisgnx(gki+1(t))迭代方法获得方程解的一些新的非振动准则.并且给出了在差分方程中的应用.     

具有正负系数的时滞微分方程解的振动性与渐近性

考虑具正负系数的时滞微分方程 x'(t)+p(t)x(t-)-q(t)x(t-r)=0,(1)其中p,q∈C([t_0,∞),R~+),τ,r∈R~+=[0,∞).我们获得了(1)的所有解振动的充分条件.也研究了(1)的所有非振动解的渐近性.     

里卡蒂方法研究带泛函参数的非线性脉冲时滞双曲方程的振动性

本文研究了带泛函参数的非线性脉冲时滞双曲方程的振动性问题.利用积分平均法和里卡蒂方法得到了这类方程解的振动性的一个充分条件,对非线性时滞双曲方程解的震动性进行了推广,能更好地利用一些现有的脉冲时滞常微分方程解的振动性的结论.     

具有分段常数变元的时滞微分方程解的振动性(英文)

我们获得了带有分段常数变元的时滞微分方程ｘ′（ｔ）＋ａ（ｔ）ｘ（ｔ）＋∑ｍｉ＝１ｂｉ（ｔ）ｘ（［ｔ－ｉ］）＝０，ｔ≥０所有解振动的新的充分条件，这里［·］定义为最大整数函数．我们的结果改进了文献中的某些已知结果．     

带有阻尼项的偏泛函微分方程解的振动性

本文研究带有阻尼项的双曲型时滞偏微分方程 2 t2 u(x,t) +m(t) u t=a(t)△ u(x,t) +b(t)△ u(x,ρ(t) ) -q(t) f (u(x,σ(t) ) ,(x,t)∈ G≡Ω× R+ (1 )其中 ,R+=[0 ,+∞ ) ,Ω是一个具有逐段光滑边界的有界区域 .利用平均法和微分不等式方法得到方程 (1 )的若干新的振动准则 .     

Oscillation theory of first order functional differential equations with deviating arguments

Summary New oscillation criteria are established for the first order functional differential equation (*) y'(t)+p(t)y(g(t))=0and its nonlinear analogue. The results are presented so that a remarkable duality existing between the case where (*) is retarded (g(t)t) is apparent. Possible extension of the results for (*) to equations with several deviating arguments is attempted. Finally, it is shown that there exists a class of autonomous equations for which the oscillation situation can be completely characterized.     

一类生物医学模型方程的稳定性和振动性

给出具有分段常数变元的二阶中立型微分方程(1)是渐近稳定的必要充分条件和方程(1)的每一解均为振动的若干充分条件.     

On numerical approximation using differential equations with piecewise-constant arguments

In this paper we give a brief overview of the application of delay differential equations with piecewise constant arguments (EPCAs) for obtaining numerical approximation of delay differential equations, and we show that this method can be used for numerical approximation in a class of age-dependent population models. We also formulate an open problem for stability and oscillation of a class of linear delay equations with continuous and piecewise constant arguments. This research was partially supported by Hungarian NFSR Grant No. T046929.     

Oscillatory properties of first order linear functional differential equations

Oscillatory properties of retarded and advanced functional differential equations are investigated.In the first part, the study concerns equations with piecewise constant arguments, which found applications in certain biomedical problems. Then, results of some authors are generalized for general equations with many argument deviations. Finally, applications are given to equations with linear transformations of the argument.     

Global asymptotic stability beyond 3/2 type stability for a logistic equation with piecewise constant arguments

In this paper, a logistic equation with multiple piecewise constant arguments is investigated in detail. We generalize the approach in two papers, [K. Uesugi, Y. Muroya, E. Ishiwata, On the global attractivity for a logistic equation with piecewise constant arguments, J. Math. Anal. Appl. 294 (2) (2004) 560-580] and [Y. Muroya, E. Ishiwata, N. Guglielmi, Global stability for nonlinear difference equations with variable coefficients, J. Math. Anal. Appl. 334 (1) (2007) 232-247], and establish a new condition for the global stability of the equation. Their results are given as one of the special cases. Moreover, we improve the 3/2 type stability condition under several dominance assumptions on the coefficients of the equation. Some examples and numerical simulations are also presented. All of these examples show that there are several conditions for the global stability of the equation, depending on the coefficients on the delay terms of the equation, beyond the 3/2 type stability condition.     

Nonlocal boundary value problems for second-order functional differential equations

We study the existence of a solution to a nonlocal boundary value problem for a class of second-order functional differential equations with piecewise constant arguments. The equation studied includes terms depending on the derivative as well as delay arguments in the derivative.