N维非线性时滞分数阶微分方程初值问题的全局解

微分方程初值问题全局解的存在性是研究李雅普诺夫意义下稳定性的先决条件。该文旨在研究初值问题(1.10)-(1.11)全局解的存在性.首先得到了初值问题(1.10)-(1.11)局部解的存在性,推广了文献[14]的结果;然后基于得到的延拓定理,证明了初值问题(1.10)-(1.11)全局解的存在性和唯一性.     

移动环境下带有非局部扩散项和时滞的反应扩散方程的强迫行波解北大核心CSCD

该文考虑了移动环境下带有非局部扩散项和时滞的反应扩散方程的强迫行波解的存在性和唯一性.首先利用上下解方法和单调迭代原理得到强迫行波解的存在性,其中,该强迫行波解以环境移动的速度来变化.其次,该文结合最大值原理,利用挤压方法得到了该强迫行波解的唯一性.最后,作为该文得到的结论的应用,该文给出了两个经典的模型,一个是带非局部扩散项和时滞的Logistic模型,另一个是带有非局部扩散项和时滞的quasi-Nicholson’s Blowfiles人口模型.     

三维流体-粒子相互作用模型:Flowing Regime模型的局部解问题

该文主要研究了三维流体-粒子相互作用模型:Flowing Regime模型在全空间中的Cauchy问题.证明了局部强解的存在性和唯一性,通过推导强解的光滑性得到了一个局部经典解.     

与年龄相关的非线性时变种群发展方程解的存在与唯一性

该文讨论了与年龄相关的非线性时变种群发展方程,证明了其局部解和整体解的存在性与唯一性及稳定性. 其结果可为种群问题的实际研究提供严格的理论基础．      

一类泛函微分方程的周期解的存在性、唯一性及全局吸引性

该文研究了一类具有分布滞量的微分系统的周期解的存在性、唯一性及全局吸引性等问题.利用不动点方法和Lyapunov泛函方法,建立了保证该类系统周期解的存在性、唯一性、一致稳定性及全局吸引性的充分条件.     

Ivlev型捕食系统的全局动力学分析

研究捕食者与食饵均具有线性密度制约的Ivlev型捕食动力系统.应用常微分方程定性方法,得到了正平衡点的全局稳定性和非小振幅极限环的存在唯一性的充分条件.特别地,在一定条件下,证明了极限环的存在唯一性与正平衡点的局部不稳定性是等价的,正平衡点的局部稳定性隐含它的全局稳定性,因此,系统的全局动力学性质完全由正平衡点的局部性质所决定.     

含有时滞的CES生产函数的资产投资模型解的稳定性

研究含有非局部和时滞边界条件的投资控制模型在解的存在唯一性基础上,讨论了模型解的稳定性,得到解的渐进稳定性.     

关于k-Hessian方程C~(2+α)局部解的存在性

该文克服椭圆型k-Hessian算子的线性化算子不满足极大值原理的困难,利用NashMoser迭代,证明当非齐次项f∈C~α变号或非负时,k-Hessian方程C~(2+α)局部解的存在性,当然当f为C~∞时,存在C~∞局部解.其技巧是首先证明线性化方程解的唯一性,以此为基础得到线性化方程解的存在性,进而得到线性化方程解的高阶正则性和先验估计.     

非均匀介质中离散Fisher-KPP方程广义行波的稳定性和唯一性

本文研究具有一般时间和空间依赖性离散Fisher-KPP(Kolmogorov-Petrovsky-Piskunov简写为KPP)方程广义行波的稳定性和唯一性.首先证明此类方程严格正整体解的存在性、唯一性和稳定性;接着建立连接此唯一严格正整体解和平凡零解的广义行波的稳定性和唯一性.应用广义行波的一般性稳定性和唯一性理论,本文进而证明时间和空间周期介质中离散Fisher-KPP方程周期行波解的存在性、稳定性和唯一性,以及时间非均匀介质中离散Fisher-KPP方程广义行波的存在性、稳定性和唯一性.本文所建立的一般性稳定性和唯一性理论表明在很多情形下得到的广义行波在合适的扰动下是渐近稳定的.     

双曲型积分微分方程的一个反问题

该文研究了一类双曲型积分微分方程确定未知系数的反问题,利用Ｂａｎａｃｈ压缩映像原理证明了该问题的局部存在唯一性和稳定性。     

Global Existence of Strong Solutions of Navier-Stokes-Poisson Equations for One-Dimensional Isentropic Compressible Fluids

The authors prove two global existence results of strong solutions of the isentropic compressible Navier-Stokes-Poisson equations in one-dimensional bounded intervals. The first result shows only the existence. And the second one shows the existence and uniqueness result based on the first result, but the uniqueness requires some compatibility condition. In this paper the initial vacuum is allowed, and T is bounded.     

UNIQUENESS ON ZERO PRESSURE GAS DYNAMICS

In this papert we study a 2 x 2 hyperbolic systenlwhere p 2 0 and u are density al1d velocity of gases, respective1y.The systen1 of conservatiou laws (1) is called pressureless fiow or pressureless gases. Itis forlllally obtailled by letting pressure to zero ill tl1e compressible Euler equations. It is alsoknown as sticky particle model in astrophysics (see [21] ).Olle Of the main difficulties for the mathematical analysis of (1) is that the solution is lloll-negative llleasurel uot function.…     

On the existence and uniqueness of smooth solution for a generalized Zakharov equation

The paper deals with the existence and uniqueness of smooth solution for a generalized Zakharov equation. We establish local in time existence and uniqueness in the case of dimension d=2,3. Moreover, by using the conservation laws and Brezis-Gallouet inequality, the solution can be extended globally in time in two dimensional case for small initial data. Besides, we also prove global existence of smooth solution in one spatial dimension without any small assumption for initial data.     

一个肿瘤生长自由边界问题解的整体存在性和唯一性

该文研究一个反应扩散方程组的自由边界问题,它来源于描述抑制物作用下无坏死核肿瘤生长的数学模型.作者运用抛物型方程的L_p理论和压缩映照原理,证明了这个问题局部解的存在唯一性,然后用延拓方法得到了整体解的存在唯一性.     

THE LOCAL AND GLOBAL EXISTENCE OF THE SOLUTIONS OF HYPERBOLIC-PARABOLIC SYSTEM MODELING BIOLOGICAL PHENOMENA

The authors prove the local existence and uniqueness of weak solution of a hyperbolic-parabolic system and establish the global existence of the weak solution for this system for the spatial dimension n = 1.     

The cauchy problem for a shallow water type equation

We prove existence and uniqueness of local and global solutions of the periodic Cauchy problem for a higher order shallow water type equation under low regularity initial data. Using Fourier analysis we first prove local estimates in appropriate spaces and then use a contraction mapping argument and a conserved norm to get global existence.     

REMARKS ON THE EXISTENCE OF WEAK SOLUTIONS TO 2-D INCOMPRESSIBLE NAVIER-STOKES EQUATIONS

1.IntroductionConsiderthefollowinghomogeneous2-DincompressibleNavier-Stokesequations:whereV=(VI(t,x),VZ(t,x))isthevelocityofthefluid,Pisthescalarpressure,V'V=V101 V202,andtheconstantu>0isthekineticviscosityofthefluid(whenu=0,thissystemiscalledEulerequations,andwedenoteitby(1.1)).Byactingtheoperationofcurlon(1.1),wecanobtaintheevolutionequationforvorticityw=(a1VZ--02VI).Itisthevorticity-streamformof(1.1)(whenu=0,wedenoteitby(1.2)).For(1.1),in[4],R.DipernaandA.Majdaprovedtheglobalexiste…     

Study of weak solutions for a fourth-order parabolic equation with variable exponent of nonlinearity

The aim of this paper is to study the existence and uniqueness of weak solutions for an initial boundary problem of a fourth-order parabolic equation with variable exponent of nonlinearity. First, the authors of this paper apply Leray-Schauder’s fixed point theorem to prove the existence of solutions of the corresponding nonlinear elliptic problem and then obtain the existence of weak solutions of nonlinear parabolic problem by combining the results of the elliptic problem with Rothe’s method. In addition, the authors also discuss the regularity of weak solutions in the case of space dimension one.     

Initial boundary value problem for modified Zakharov equations

In this paper the authors consider the existence and uniqueness of the solution to the initial boundary value problem for a class of modified Zakharov equations, prove the global existence of the solution to the problem by a priori integral estimates and Galerkin method.     

Regularity properties of the Zakharov system on the half line

In this paper, we study the local and global regularity properties of the Zakharov system on the half line with rough initial data. These properties include local and global wellposedness results, local and global smoothing results, and the behavior of higher order Sobolev norms of the solutions. Smoothing means that the nonlinear part of the solution on the half line is smoother than the initial data. The gain in regularity coincides with the gain that was observed for the periodic Zakharov and the Zakharov on the real line. Uniqueness is proved in the class of smooth solutions. When the boundary value of the Schrödinger part of the solution is zero, uniqueness can be extended to the full range of local solutions. Under the same assumptions on the initial data, we also prove global-in-time existence and uniqueness of energy solutions. For more regular data, we prove that all higher Sobolev norms grow at most polynomially-in-time.