Global attractivity in a perturbed linear delay differential equation

In the main result of this paper, some sharp conditions are obtained for global attractivity in a scalar perturbed linear delay differential equation. The proof of the main theorem is based on a new estimate for the infinite integral of the absolute value of the fundamental solution of a linear delay differential equation. We also derive sufficient conditions for asymptotic stability of a system of linear delay differential equations.     

Asymptotic properties of solutions to linear non-autonomous neutral differential equations

In this article we study asymptotic properties of solutions to first order linear neutral differential equations with variable coefficients and constant delays. Results are stated in terms of the solution to a characteristic equation. By doing this, we extend some of the results obtained for delay equations in [J.G. Dix, Ch.G. Philos, I.K. Purnaras, An asymptotic property of solutions to linear non-autonomous delay differential equations, Electron. J. Differential Equations 2005 (2005) 1-9] to neutral equations.     

Some new results on an allelopathic competition model with quorum sensing and delayed toxicant production

A 4-equation delay differential system representing a bacterial allelopathic competition is analyzed. A distributed delay term models a linear quorum-sensing mechanism which regulates the delayed allelochemicals’ production process. The proved qualitative properties of the solutions are positivity, boundedness, global existence in the future, and uniqueness. Sufficient conditions for local asymptotic stability properties of biologically meaningful steady-state solutions are given in terms of the parameters of the system. The global asymptotic stability of a biologically meaningful steady-state solution is proved by constructing a suitable Lyapunov functional.     

Admissible Domains for Higher Order Differential Equations

This paper analyzes the geometric structure of certain domains in the complex plane which arise in the asymptotic theory of linear ordinary differential equations containing a parameter. These domains, called admissible, are domains in which an asymptotic representation of the solution of the differential equation may be found and across whose boundaries these representations may undergo a rapid change of asymptotic behavior (the Stokes phenomenon). A knowledge of the disposition of those domains associated with a particular differential equation is necessary for a satisfactory asymptotic theory of the equation. The main analysis gives necessary and sufficient conditions for identifying admissible domains and gives a procedure for obtaining particular admissible subdomains of a given domain. Sufficient conditions are established to determine the maximality of admissible domains. A section of examples is included to highlight the salient features of this theory. In all of the results, criteria involving only purely local properties of the boundary are needed to determine the global properties of admissibility and maximal admissibility .     

线性时滞微分方程解的渐近性态

本文用一个简单的方法证明了一类一阶线性时滞微分方程解的有界性帮必有非振动解，分析了振动解的性质。这个方法也被用来讨论一阶时滞方程组和中立型微分方程，所得结果均较简明。     

On generalized Eisenstein series and Ramanujan’s formula for periodic zeta-functions

We construct the asymptotic formulas for solutions of a certain linear second-order delay differential equation as independent variable tends to infinity. When the delay equals zero this equation turns into the so-called one-dimensional Schrödinger equation at energy zero with Wigner–von Neumann type potential. The question of interest is how the behaviour of solutions changes qualitatively and quantitatively when the delay is introduced in this dynamical model. We apply the method of asymptotic integration that is based on the ideas of the centre manifold theory in its presentation with respect to the systems of functional differential equations with oscillatory decreasing coefficients.     

Periodic first order linear neutral delay differential equations

Some new asymptotic and stability results are given for a first order linear neutral delay differential equation with periodic coefficients and constant delays. The asymptotic behavior of the solutions and the stability of the trivial solution are described by the use of an appropriate real root of an equation, which is in a sense the corresponding characteristic equation.     

Asymptotic stability for delayed logistic type equations

We study the stability of scalar delayed equations of logistic type with a positive equilibrium and a linear logistic term. The global asymptotic stability of the positive equilibrium, called the carrying capacity, is proven imposing a condition on a negative feedback term without delay dominating the delayed effect. It turns out that this assumption is a necessary and sufficient condition for the linearized equation about the positive equilibrium to be asymptotically stable, globally in the delays. The global stability of more general scalar delay differential equations is also addressed.     

Asymptotic Stability of Runge-Kutta Methods for the Pantograph Equations

This paper considers the asymptotic stability analysis of both exact and numerical solutions of the following neutral delay differential equation with pantograph delay.where $B,C,D\in C^{d\times d},q\in (0,1)$,and $B$ is regular. After transforming the above equation to non-automatic neutral equation with constant delay, we determine sufficient conditions for the asymptotic stability of the zero solution. Furthermore, we focus on the asymptotic stability behavior of Runge-Kutta method with variable stepsize. It is proved that a L-stable Runge-Kutta method can preserve the above-mentioned stability properties.     

An asymptotic property of the solutions to second order linear nonautonomous delay differential equations

Second order linear nonautonomous delay differential equations are considered, and a fundamental asymptotic criterion for the solutions is established, by the use of the concept of generalized characteristic equation.     

Stability of Stochastic Delay Differential Equation with a Small Parameter

Abstract

Stochastic delay differential equations with wideband noise perturbations is considered. First it is shown that the perturbed system converges weakly to a stochastic delay differential equation driven by a Brownian motion. Stability and asymptotic properties of stochastic delay differential equations with a small parameter are developed. It is shown that the properties such as stability, recurrence, etc., of the limit system with time lag is preserved for the solution x ^?(·) of the underlying delay equation for ? > 0 small enough. Perturbed Liapunov function method is used in the analysis.     

EXPONENTIAL STABILITY OF LINEAR TIME－VARYING IMPULSIVE DIFFERENTIAL SYSTEMS WITHDELAYS

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On time transformations for differential equations with state-dependent delay

Systems of differential equations with state-dependent delay are considered. The delay dynamically depends on the state, i.e. is governed by an additional differential equation. By applying the time transformations we arrive to constant delay systems and compare the asymptotic properties of the original and transformed systems.     

Asymptotic stability of a mechanical robotics model with damping and delay

In this paper we study the asymptotic stability of a mechanical robotics model with damping and delay. This model yields a certain linear third order delay differential equation. In proving our results we make use of Pontryagin's theory for quasi-polynomials.     

Asymptotic Properties of the Nonoscillatory Solutions of Second-Order Neutral Equations with a Deviating Argument

In the paper second-order linear neutral differential equations with a distributed delay are considered. The asymptotic properties of their nonoscillatory solutions are investigated.     

Global asymptotic stability for a periodic delay hematopoiesis model with impulses

In this paper, sufficient conditions for the global asymptotic stability of a broad family of periodic impulsive scalar delay differential equations are obtained. These conditions are applied to a periodic hematopoiesis model with multiple time-dependent delays and linear impulses, in order to establish criteria for the global asymptotic stability of a positive periodic solution. The present results are discussed within the context of recent literature. In conclusion, when compared with previous works, not only sharper stability criteria are obtained here, even for models without impulses, but also the usual constraints imposed on the linear impulses are relaxed.     

On the dominance of roots of characteristic equations for neutral functional differential equations

We present a sufficient condition for a zero of a function that arises typically as the characteristic equation of a linear functional differential equations of neutral type, to be simple and dominant. This knowledge is useful in order to derive the asymptotic behaviour of solutions of such equations. A simple characteristic equation, arisen from the study of delay equations with small delay, is analyzed in greater detail.     

Existence,uniqueness and global asymptotic stability of positive solutions of a predator–prey system with Holling II functional response with random perturbation

This paper discusses a randomized two-species predator–prey system with Holling II functional response. We show that the positive solution of the associated stochastic delay differential equation does not explode to infinity in a finite time. In addition, the existence, uniqueness and global asymptotic stability of the positive solutions are studied.     

含时滞的线性偏泛函微分方程解的渐近行为

本文对一类含有时滞的抛物偏泛函微分方程解的渐近行为进行了讨论。分别就两种不同的边界条件，采用Ｌｉａｐｕｎｏｖ泛函及Ｌ—ｐ—估计，获得了其解全局稳定、振动的若干简洁充分条件     

Global existence of small solutions to nonlinear evolution equations

We study the global existence and asymptotic behaviour of “small” solutions of a large class of nonlinear partial differential equations. If the nonlinear terms are of high degree the solutions will be asymptotic to solutions of the linear equation.