具有可变时滞的非线性非自治差分方程的线性化全局渐近稳定性及其应用

证明了在一定条件下,具有可变时滞的非线性非自治差分方程的全局渐近稳定性可由某种线性差分方程的渐近稳定性确定,给出了这类差分方程全局渐近稳定的充分条件.作为实例,获得了具有可变时滞的离散型非自治广义Log istic方程的全局吸收性判别准则.     

多值半流理论及其在三维Navier-Stokes方程中的应用

利用多值半流方法研究三维有界区域上Navier-Stokes方程的全局吸引子,证得了多值半流的一些性质,并将这些性质应用于三维Navier-Stokes方程,得出了弱解的几种全局吸引子.从而表明在三维情形,通过多值半流来研究Navier-Stokes方程的全局吸引子是可行的.     

阻尼Navier-Stokes方程全局吸引子的正则性（英文）

本文研究阻尼Navier-Stokes方程全局吸引子问题.利用迭代法和线性算子半群的正则性估计,结合经典的全局吸引子理论,证明了阻尼NS方程在H~k空间中存在全局吸引子,并在H~k范数下吸引任意有界集.     

一类广义时滞 Logistic 方程的全局吸引性

本文研究了一类广义时滞Logistic方程的全局吸引性,获得了该方程的正平衡点全局吸引的一个充分条件,对已有的结果进行了改进和推广.     

弱耗散抽象发展方程全局吸引子的存在性

采用定义泛函,忽略粘性阻尼项时,在特定空间中研究了弱耗散抽象发展方程,得到了该方程全局吸引子的存在性结论,丰富了该类方程全局吸引子存在性的证法.     

热盐环流方程全局弱解的存在性

该文利用T-弱连续算子理论和空间序列方法证明了热盐环流方程全局弱解的存在性.首先根据热盐环流方程的形式选择试探函数空间和解函数空间,再将方程化为抽象的算子方程,验证算子是T-弱连续的并满足对应条件,从而得到热盐环流方程全局弱解的存在性.     

具有外磁场的Landau-Lifshitz方程

本文研究具有外磁场的Landau-Lifshitz方程的全局动力学,具体包括局部适定性、全局适定性、周期解的存在性.首先,利用移动标架法将LandauLifshitz方程转化为半线性Schr?dinger方程,从而利用色散方程的技巧得到任意维的局部适定性和一维的全局适定性.其次,通过使用Landau-Lifshitz方程的对称性将周期解的存在性转化为常微分方程,从而证明了具有非零常值外磁场的Landau-Lifshitz方程具有非平凡的周期解,同时对于时间相关的外磁场,我们构造了若干具有典型动力学意义的特解.     

二阶非线性差分方程的全局吸引性

[摘　要] 研究了差分方程xn+1=a-bxn-1A-xn(a≥0,A≥b≥0)的全局稳定性和正解的周期性.证明了方程的一个正平衡点是一个全局吸引子,并给出了相应的吸引域.     

高阶变形的Novikov方程弱解的全局存在性

研究了一类高阶变形的Novikov方程全局弱解的存在性,在初值满足条件u0∈H2,p,p 4时,通过黏性逼近的方法得到了高阶变形Novikov方程全局弱解的存在性.     

阻尼KDV-Burgers方程全局吸引子的维数[英文]

本文研究定义在$\mathbb{R}$上KdV-Burgers方程全局吸引子的分形维数, 利用Chueshov和Lasiecka提出的拟稳态估计方法证明方程全局吸引子分形维数在$H^1$空间中有限.     

GLOBAL ATTRACTIVITY OF A DIFFERENCE EQUATION

In this paper,we investigate the global stability of all positive solutions to a difference equation.We show that the unique positive equilibrium of the equation is a global attractor with a basin under some certain conditions on the coefficient.     

高阶非线性差分方程的全局吸引性

研究了差分方程 xn 1 =a - bxn- k A - xn( a≥ 0 ,A≥ b≥ 0 )的全局稳定性和正解的周期性质 .证明了方程的一个正平衡点是一个全局吸引子 ,并给出了相应的吸引域     

一类半线性椭圆型方程正整体解的存在性

本文研究了一个半线性椭圆型方程正整体解的存在性问题.利用上下解方法克服了非齐次项出现带来的困难,获得了正整体解存在的必要条件,具体地给出了在此条件下正整体解所处的领域.     

多滞量高阶非线性差分方程的全局吸引性

研究了差分方程xn+1=(a+bxn)/(A+B xn-k)(C+D xn-l),n=0,1,2,….其中a,b,A,B,C∈(0,∞),D∈[0,∞),k,l是正整数,初值条件x-k,…,x-1及x0是任意正常数的全局吸引性,推广了相关文献的相关结果.     

Global Dynamics of a Novel Delayed Logistic Equation Arising from Cell Biology

The delayed logistic equation (also known as Hutchinson’s equation or Wright’s equation) was originally introduced to explain oscillatory phenomena in ecological dynamics. While it motivated the development of a large number of mathematical tools in the study of nonlinear delay differential equations, it also received criticism from modellers because of the lack of a mechanistic biological derivation and interpretation. Here, we propose a new delayed logistic equation, which has clear biological underpinning coming from cell population modelling. This nonlinear differential equation includes terms with discrete and distributed delays. The global dynamics is completely described, and it is proven that all feasible non-trivial solutions converge to the positive equilibrium. The main tools of the proof rely on persistence theory, comparison principles and an $$L^2$$-perturbation technique. Using local invariant manifolds, a unique heteroclinic orbit is constructed that connects the unstable zero and the stable positive equilibrium, and we show that these three complete orbits constitute the global attractor of the system. Despite global attractivity, the dynamics is not trivial as we can observe long-lasting transient oscillatory patterns of various shapes. We also discuss the biological implications of these findings and their relations to other logistic-type models of growth with delays.     

Global bifurcation of solutions of the mean curvature spacelike equation in certain Friedmann–Lemaître–Robertson–Walker spacetimes

We study the existence of spacelike graphs for the prescribed mean curvature equation in the Friedmann–Lemaître–Robertson–Walker (FLRW) spacetime. By using a conformal change of variable, this problem is translated into an equivalent problem in the Lorentz–Minkowski spacetime. Then, by using Rabinowitz's global bifurcation method, we obtain the existence and multiplicity of positive solutions for this equation with 0-Dirichlet boundary condition on a ball. Moreover, the global structure of the positive solution set is studied.     

An Upper Bound for Hessian Matrices of Positive Solutions of Heat Equations

We prove global and local upper bounds for the Hessian of log positive solutions of the heat equation on a Riemannian manifold. The metric is either fixed or evolved under the Ricci flow. These upper bounds seem to be the first general ones that match the well-known lower bounds which have been around for some time. As an application, we discover a local, time reversed Harnack type inequality for bounded positive solutions of the heat equation.     

PROPERTIES OF POSITIVE SOLUTIONS FOR A NONLOCAL NONLINEAR DIFFUSION EQUATION WITH NONLOCAL NONLINEAR BOUNDARY CONDITION

This article deals with the global existence and blow-up of positive solution of a nonlinear diffusion equation with nonlocal source and nonlocal nonlinear boundary condition. We investigate the influence of the reaction terms, the weight functions and the nonlinear terms in the boundary conditions on global existence and blow up for this equation. Moreover, we establish blow-up rate estimates under some appropriate hypotheses.     

GLOBAL ATTRACTIVITY IN A CLASS OF HIGHER-ORDER NONLINEAR DIFFERENCE EQUATION

In this paper the global attractivity of the nonlinear difference equation xn 1 = a bxn / A xn-k, n =0, 1, …，is investigated, where a, b, A ∈ (0, ∞), k is an positive integer and the initial conditions x- k, …，x- 1 and x0 are arbitrary positive numbers. It is shown that the unique positive equilibrium of the equation is global attractive. As a corollary, the result gives a positive confirmation on the conjecture presented by Kocic and Ladas [1,p154].