Results 241 to 250 of about 524,417 (274)

Asymptotic Profiles for Positive Solutions in Periodic-Parabolic Problem

Journal of Dynamics and Differential Equations, 2022
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Positive doubly periodic solutions of nonlinear telegraph equations

Nonlinear Analysis: Theory, Methods & Applications, 2003
This interesting paper discusses the existence of (weak) solutions (i.e. understood in the distribution sense) to the nonlinear telegraph equation \[ u_{tt}- u_{x,x}+cu_t= -a(t, x)u+ b(t, x) f (t, x, u), \] \((t, x)\in \mathbb{R}^2\) being positive doubly periodic, i.e.
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On Positive Periodic Solutions for Nonlinear Delayed Differential Equations

Mediterranean Journal of Mathematics, 2015
Positive \(\omega-\)periodic solutions of the equation \[ \dot x(t) = a(t) g(x(t))x(t) - \lambda b(t) f[x(t-\tau(t))] \] are obtained under the assumption that \(a, b\) and \(\tau\) are nonnegative and \(\omega\)-periodic, and under less restrictive assumptions on the nonlinear functions \(f,g\) than in previous papers.
Hai, D. D., Qian, C.
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STABLE POSITIVE PERIODIC SOLUTION OF TIME DEPENDENT LOTKA-VOLTERRA PERIODIC MUTUALISTIC SYSTEM

Acta Mathematica Scientia, 1994
The main result of this paper is: Consider a Lotka-Volterra mutualistic system in a periodic environment, \(dx_ i/dt = x_ i\) \((r_ i(t) + \sum^ n_{j = 1} a_{ij} (t)x_ j)\) \((i = 1, \dots, n)\), with \(a_{ii} (t) < 0\) and \(a_{ij} (t) \geq 0\) \((i \neq j)\) and with \(\omega\)-periodic \((0 < \omega < + \infty)\) functions \(r_ i (t)\) and \(a_{ij} (
Cui, Jing'an, Chen, Lansun
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Positive periodic solution of a neutral predator-prey system

Applied Mathematics and Mechanics, 1999
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POSITIVE PERIODIC SOLUTIONS OF PREDATOR-PREY SYSTEMS WITH INFINITE DELAY

Chinese Annals of Mathematics, 2000
Conditions for the existence of positive periodic solutions to a nonautonomous non-convolution predator-prey system with infinite delay \[ \begin{aligned} x'(t) &= x(t)[a(t)-b(t)x(t)-c(t)y(t)],\\ y'(t) &= y(t)[-d(t)+\int_{-\infty}^{t} K(s,t,x(s),x(t)) ds], \end{aligned} \] under certain assumptions on the functions \(K,a,b,c,d\) are given.
Wang, Ke, Fan, Meng
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The periodic Riccati equation: Existence of a periodic positive sernidefinite solution

26th IEEE Conference on Decision and Control, 1987
In this paper, the existence of a positive semidefinite periodic solution of the periodic Riccati differential equation is dealt with. Precisely, a necessary and sufficient condition is given in terms of the asymptotic stability of the observable and uncontrollable part of the underlying system.
S. Bittanti, P. Colaneri, G. Nicolao
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Positive Periodic Solution for a Nonautonomous Delay Differential Equation

Acta Mathematicae Applicatae Sinica, English Series, 2003
By means of Krasnoselskii's fixed-point theorem, this paper explores the existence of one or multiple positive periodic solutions of nonautonomous differential equations with multiple time lags of the form \[ y'(t)=-a(t)y(t)+f(t,y(t-\tau_1(t)),\dots,y(t-\tau_n(t))) \] and \[ y'(t)=a(t)y(t)-f(t,y(t-\tau_1(t)),\dots,y(t-\tau_n(t))), \] where \(a\in C ...
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Positive periodic solutions of first-order singular systems

Applied Mathematics and Computation, 2012
This paper deals with existence and the number of periodic solutions of the first order system \[ u'_i(t)=-a_i(t)u_i(t)+\lambda b_i(t)f_i(\vec u(t)),\quad i=1,\,\dots,\,n\eqno(1) \] where \(\vec u=(u_1,\,\dots,\,u_n)\in{\mathbb R}^n\), \(a_i\) and \(b_i\) are continuous \(T\)-periodic functions with positive mean value in a period, \(f_i: {\mathbb R}^n\
Chen, Ruipeng, Ma, Ruyun, He, Zhiqian
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Positive periodic solutions of periodic neutral Lotka–Volterra system with distributed delays

Chaos, Solitons & Fractals, 2008
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