Semigroup Properties and the Crandall Liggett Approximation for a Class of Differential Equations with State-Dependent Delays

We present an approach for the resolution of a class of differential equations with state-dependent delays by the theory of strongly continuous nonlinear semigroups. We show that this class determines a strongly continuous semigroup in a closed subset of C^0, 1. We characterize the infinitesimal generator of this semigroup through its domain. Finally, an approximation of the Crandall-Liggett type for the semigroup is obtained in a dense subset of (C, ‖·‖_∞). As far as we know this approach is new in the context of state-dependent delay equations while it is classical in the case of constant delay differential equations.     

Attractors for Differential Equations with Variable Delays

Using the relatively new concept of a pullback attractor, we present some results on the existence of attractors for differential equations with variable delay. We give a variety of examples to which our result applies.     

混合单调半流与泛函微分方程的稳定性

本文首先提出混合单调半流的概念和泛函微分方程生成这种半流的条件。然后，利用半流的混合单调性，我们得到关于泛函微分方程的渐近稳定性和全局稳定性的新结果．     

Approximate Controllability of Fractional Differential Equations with State-Dependent Delay

The systems governed by delay differential equations come up in different fields of science and engineering but often demand the use of non-constant or state-dependent delays. The corresponding model equation is a delay differential equation with state-dependent delay as opposed to the standard models with constant delay. The concept of controllability plays an important role in physics and mathematics. In this paper, first we study the approximate controllability for a class of nonlinear fractional differential equations with state-dependent delays. Then, the result is extended to study the approximate controllability fractional systems with state-dependent delays and resolvent operators. A set of sufficient conditions are established to obtain the required result by employing semigroup theory, fixed point technique and fractional calculus. In particular, the approximate controllability of nonlinear fractional control systems is established under the assumption that the corresponding linear control system is approximately controllable. Also, an example is presented to illustrate the applicability of the obtained theory.     

时滞矩阵微分方程的等度稳定性

在矩阵值范数定义的广义赋范空间上利用矩阵Liapunov泛函研究了时滞矩阵微分方程的等度稳定性,得出了若干新结果.     

Slowly Oscillating Solutions of Differential Equations with Delays

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Continuous Dependence for Stochastic Functional Differential Equations with State-Dependent Regime-Switching on Initial Values

This work is concerned with the continuous dependence on initial values of solutions of stochastic functional differential equations(SFDEs) with state-dependent regime-switching. Due to the state-dependence, this problem is very different to the corresponding problem for SFDEs without switching or SFDEs with Markovian switching. We provide a method to overcome the intensive interaction between the continuous component and the discrete component based on a subtle application of Skorokhod's representation for jumping processes. Furthermore, we establish the strong convergence of Euler–Maruyama's approximations, and estimate the order of error. The continuous dependence on initial values of Euler–Maruyama's approximations is also investigated in the end.     

一类n阶非线性时滞微分方程周期解的存在性

通过应用拓扑度的方法, 获得了一类n阶非线性时滞微分方程2π周期解存在性的若干结论.     

Computing Stability of Differential Equations with Bounded Distributed Delays

This paper deals with the stability analysis of scalar delay integro-differential equations (DIDEs). We propose a numerical scheme for computing the stability determining characteristic roots of DIDEs which involves a linear multistep method as time integration scheme and a quadrature method based on Lagrange interpolation and a Gauss–Legendre quadrature rule. We investigate to which extent the proposed scheme preserves the stability properties of the original equation. We derive and prove a sufficient condition for (asymptotic) stability of a DIDE (with a constant kernel) which we call RHP-stability. Conditions are obtained under which the proposed scheme preserves RHP-stability. We compare the obtained results with corresponding ones using Newton–Cotes formulas. Results of numerical experiments on computing the stability of DIDEs with constant and nonconstant kernel functions are presented.     

多时滞抛物型微分方程的强迫振动

我们给出满足某种边界条件的非线性时滞抛物型微分方程的一切解振动的若干充分条件.     

多时滞高阶微分方程的周期解

By Fourier analysis techniques and Schauder fixed point theorem, we study the existence of periodic solutions for a class of even order differential equations with multiple delays. The result obtained is a generalization of the results developed by W. Layton to the case of multiple delays.     

一类多时滞微分方程初值问题解的存在唯一性

研究了一类多时滞微分方程初值问题解的存在唯一性,用Picard方法证明了这类初值问题解的存在唯一性结论,它是常微分方程基本理论中著名的Picard存在唯一性定理的推广.     

多时滞微分方程数值稳定性

考虑了时滞微分方程的初值问题,分析了用线性多步法求解一类滞后型微分系统数值解的稳定性,在一定的Lagrange插值条件下,给出并证明了求解滞后型微分系统的线性多步法数值稳定的充分必要条件.     

Asymptotic Behavior of Solutions of Differential Equations with Variable Delays

The authors consider the system of forced differential equationswith variable delays whereB_j(t) is a continuous n x n matrix on R⁺, F C(R⁺, Rⁿ) and C(R⁺, R⁺). Using Razumikhin-type techniques and Liapunov'sdirect method, they establish conditions to ensure the ultimateboundedness and the global attractivity of solutions of (*),and when F(t) = 0, the asymptotic stability of the zero solution.Under those same conditions, they also show that is a necessary and sufficient condition for allof the above properties to hold. 1991 Mathematics Subject Classification:34K15, 34C10.     

$n$-维中立型多时滞微分方程的稳定性分析

This paper is mainly concerned with stability analysis of neutral differential equations with multiple delays. Some criteria on instability, stability, asymptotic stability and exponential stability are obtained. The criterion on asymptotic stability is necessary and sufficient. Two examples are provided to illustrate the applications of our results. Some previous results are extended.     

On Positive Periodic Solutions to Impulsive Differential Equations with Delays

In this paper, by using the Krasnoselskii fixed point theorem on cone compression and expansion, we study the existence of positive periodic solutions of differential equations with impulses and delays, and obtain some new results.