On the Solutions of a Second Order Differential Equation Arising in the Theory of Resonant Oscillations in a Tank

The properties of the solutions of the differential equation y″ = y² ? x² ? c subject to the condition that y is bounded for all finite x discussed. The arguments of Holmes and Spence have been used by Ockendon, Ockendon, and Johnson to show that there are no solutions if c is large and negative. Numerically we find that solutions exist provided c is greater than a critical value c* and estimate this value to be c* = ?…. As x tends to + ∞ the solutions are asymptotic to . The relation between A₊ and ?₊ are found analytically as A₊ → ∞. This problem arises as a connection problem in the theory of resonant oscillations of water waves.     

The Boundedness of Solutions of a Lienard Equation Arising in the Theory of Ship Rolling

A theorem is proved that gives conditions for the existenceof a Lyapunov envelope that bounds solutions of an equationof the Liénard type in which the restoring coefficientmay change sign. An application of the theorem to ship rollingmotion is given.     

Initial-Value Technique for Singularly Perturbed Boundary-Value Problems for Second-Order Ordinary Differential Equations Arising in Chemical Reactor Theory

An initial-value technique is presented for solving singularly perturbed two-point boundary-value problems for linear and semilinear second-order ordinary differential equations arising in chemical reactor theory. In this technique, the required approximate solution is obtained by combining solutions of two terminal-value problems and one initial-value problem which are obtained from the original boundary-value problem through asymptotic expansion procedures. Error estimates for approximate solutions are obtained. Numerical examples are presented to illustrate the present technique.     

On Modular Forms Arising from a Differential Equation of Hypergeometric Type

Modular and quasimodular solutions of a specific second order differential equation in the upper-half plane, which originates from a study of supersingular j-invariants in the first author's work with Don Zagier, are given explicitly. Positivity of Fourier coefficients of some of the solutions as well as a characterization of the differential equation are also discussed.     

迁移理论中一类非线性积分方程的解的个数

在文献[1—3]里,讨论了迁移理论中一类非线性积分方程存在唯一解和多解的充分条件。本文将对方程     

The Minimal Branch of Solutions of an Equation Arising in Thermal Combustion Theory

Although the steady-state equation of thermal combustion theoryoften has multiple solutions, it is usually the minimal positivesolution which has most physical significance. For instance,an exothermically reacting system will approach this minimalsteady state if the initial temperature is not too high. Theoccurrence of discontinuities in the minimal solution branchas the parameters governing the reaction are varied often signifiesdrastic changes in the behaviour of the evolving system, andindeed this phenomenon has been equated with the onset of explosion.In this paper, it is shown that the presence of such discontinuitiesis equivalent, under quite general conditions, to the existenceof values of the thermal parameters at which multiplicity ofsolutions gives way to uniqueness.     

一类带奇异项的双调和方程的多解性

利用纤维方法及亏格理论对一类带奇异项的双调和方程进行了研究,证明了方程在两种不同情形下解的存在性及多解性.     

薛定谔方程及薛定谔-麦克斯韦方程的多解

不作周期性和对称性的假设,也没有Ambrosetti-Rabinowitz增长控制条件,我们得到了一类超线性薛定谔方程在全空间中无穷多解的存在性结果.同时,得到了一类超线性薛定谔-麦克斯韦方程无穷多解的存在性结果.     

一类拟线性椭圆方程的多重解

利用变分法和一个三临界点定理,证明了一类拟线性椭圆方程-div(a|u|p)|u|p-2u)=λf(x,u),u=0,ΩΩ,在某些新的条件下至少存在三个解,其中ΩRn(n≥1)是一个具有光滑边界的有界区域,且a∈C(R ,R),p>n,λ>0为一实参数.并给出了该结论在毛细现象中的广义Capillarity方程的一个应用.     

On Solutions of Ordinary Differential Equations Arising from a Model of Crystal Growth

The properties of the solutions of the equations φ′″ + φ′ = ?e^φ and φ′″ + φ′ = 1/(2φ) in the complex plane are discussed. Both equations have Stokes phenomena as the imaginary axis is crossed. The Stokes multiplier of the subdominant term in each case is accurately calculated by transforming the equation into an integral equation by using a Laplace integral. The existence and uniqueness of the solutions of these integral equations are also discussed.     

Properties of Solutions for a Functional Equation Arising in Dynamic Programming

This paper is concerned with a new functional equation arising in dynamic programming of multistage decision processes. Utilizing the Banach fixed point theorem and iterative algorithms, we prove the existence, uniqueness, and iterative approximations of solutions for the functional equation in Banach spaces and a complete metric space, respectively. Some error estimates between the iterative sequences generated by iterative algorithms and the solutions are discussed. Five examples are constructed to illustrate the results presented in this paper.     

On the Cross Ratio of Solutions of a First-Order Scalar Differential Equation

For a first-order scalar differential equation, a conditionis given which implies that the cross ratio of four solutionsis a monotone function.     

Classical Solutions for a Nonlinear Fokker-Planck Equation Arising in Computational Neuroscience

In this paper we analyze the global existence of classical solutions to the initial boundary-value problem for a nonlinear parabolic equation describing the collective behavior of an ensemble of neurons. These equations were obtained as a diffusive approximation of the mean-field limit of a stochastic differential equation system. The resulting nonlocal Fokker-Planck equation presents a nonlinearity in the coefficients depending on the probability flux through the boundary. We show by an appropriate change of variables that this parabolic equation with nonlinear boundary conditions can be transformed into a non standard Stefan-like free boundary problem with a Dirac-delta source term. We prove that there are global classical solutions for inhibitory neural networks, while for excitatory networks we give local well-posedness of classical solutions together with a blow up criterium. Surprisingly, we will show that the spectrum for the operator in the linear case, that corresponding to a system of uncoupled networks, does not give any information about the large time asymptotic behavior.     

关于高阶线性微分方程解的增长性

在本文中,我们研究了一类高阶齐次线性微分方程f(k) +Ak-1f(k-1)+…+Aof=0,其中Aj(z) (j=0,1,…,k-1)是有限级整函数,且存在As(z)(s∈{0,1,…,k-1))是超越的且σ(As)＜1/2或其泰勒展式为缺项级数.我们给出了方程任一解f(≠)0的增长估计.     

包含Sobolev-Hardy指数的p-Laplace方程的多解

在本文中，我们利用Sobolev-Hardy不等式，局部PS条件和亏格理论，证明了一类带临界Sobolev-Hardy指数的奇异p-Laplace方程存在多解．     

四阶差分方程边值问题解的多重性

利用一个临界点存在性定理,结合上下解方法,证明了一类非线性四阶差分方程边值问题至少有四个解.     

Infinite Multiplicity of Positive Entire Solutions for a Semilinear Elliptic Equation

We establish that the elliptic equation Δu+K(x)u^p+μf(x)=0 in Rⁿ has infinitely many positive entire solutions for small μ?0 under suitable conditions on K, p, and f.