NECESSARY AND SUFFICIENT CONDITIONS FOR OSCILLATIONS OF NEUTRAL DELAY DIFFERENTIAL EQUATIONS WITH SE

ＮＥＣＥＳＳＡＲＹＡＮＤＳＵＦＦＩＣＩＥＮＴＣＯＮＤＩＴＩＯＮＳＦＯＲＯＳＣＩＬＬＡＴＩＯＮＳＯＦＮＥＵＴＲＡＬＤＥＬＡＹＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＳＥＶＥＲＡＬＰＯＳＩＴＩＶＥＡＮＤＮＥＧＡＴＩＶＥＣＯＥＦＦＩＣＩＥＮＴＳ￥...     

OSCILLATION OF HIGHER ORDER NEUTRAL DIFFERENTIAL EQUATIONS WITH POSITIVE AND NEGATIVE COEFFICIENTS

ＯＳＣＩＬＬＡＴＩＯＮＯＦＨＩＧＨＥＲＯＲＤＥＲＮＥＵＴＲＡＬＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＰＯＳＩＴＩＶＥＡＮＤＮＥＧＡＴＩＶＥＣＯＥＦＦＩＣＩＥＮＴＳＬｉＷａｎｔｏｎｇ（李万同）（ＺｈａｎｇｙｅＴｅａｃｈｅｒｓ＇Ｃｏｌｌｅｇｅ...     

NECESSARY AND SUFFICIENT CONDITION FOR OSCILLATION OF A CLASS OF HIGHERORDER NEUTRAL EQUATIONS

ＮＥＣＥＳＳＡＲＹＡＮＤＳＵＦＦＩＣＩＥＮＴＣＯＮＤＩＴＩＯＮＦＯＲＯＳＣＩＬＬＡＴＩＯＮＯＦＡＣＬＡＳＳＯＦＨＩＧＨＥＲＯＲＤＥＲＮＥＵＴＲＡＬＥＱＵＡＴＩＯＮＳＬｉｎＹｉｚｈｏｎｇ（林宜中）（ＦｕｊｉａｎＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，福建师范...     

OSCILLATIONS OF SOLUTIONS OF NEUTRAL DIFFERENTIAL EQUATIONS WITH VARIABLE COEFFICIENTS AND DELAYS

ＯＳＣＩＬＬＡＴＩＯＮＳ　ＯＦ　ＳＯＬＵＴＩＯＮＳ　ＯＦ　ＮＥＵＴＲＡＬ　ＤＩＦＦＥＲＥＮＴＩＡＬ　ＥＱＵＡＴＩＯＮＳ　ＷＩＴＨ　ＶＡＲＩＡＢＬＥ　ＣＯＥＦＦＩＣＩＥＮＴＳ　ＡＮＤ　ＤＥＬＡＹＳ　ＯＳＣＩＬＬＡＴＩＯＮＳＯＦＳＯＬＵＴＩＯＮＳＯＦＮＥ...     

THE EXISTENCE AND UNIQUENESS AND STABILITY OF ALMOST PERIODIC SOLUTIONS FOR FUNCTIONAL DIFFERENTIAL EQUATIONS WITH INFINITE DELAYS

ＴＨＥＥＸＩＳＴＥＮＣＥＡＮＤＵＮＩＱＵＥＮＥＳＳＡＮＤＳＴＡＢＩＬＩＴＹＯＦＡＬＭＯＳＴＰＥＲＩＯＤＩＣＳＯＬＵＴＩＯＮＳＦＯＲＦＵＮＣＴＩＯＮＡＬＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＩＮＦＩＮＩＴＥＤＥＬＡＹＳＷＡＮＧＱＵＡＮＨＮＹ...     

A NECESSARY AND SUFFICIENT CONDITION OF EXISTENCE OF GLOBAL SOLUTIONS FOR SOME NONLINEAR HYPERBOLIC EQUATIONS

ＡＮＥＣＥＳＳＡＲＹＡＮＤＳＵＦＦＩＣＩＥＮＴＣＯＮＤＩＴＩＯＮＯＦＥＸＩＳＴＥＮＣＥＯＦＧＬＯＢＡＬＳＯＬＵＴＩＯＮＳＦＯＲＳＯＭＥＮＯＮＬＩＮＥＡＲＨＹＰＥＲＢＯＬＩＣＥＱＵＡＴＩＯＮＳ￥ＺＨＡＮＧＱＵＡＮＤＥ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅ...     

POSITIVE SOLUTIONS AND BIFURCATION OF FULLY NONLINEAR ELLIPTIC EQUATIONS INVOLVING SUPER－CRITICAL SOBOLEV EXPONENTS

ＰＯＳＩＴＩＶＥＳＯＬＵＴＩＯＮＳＡＮＤＢＩＦＵＲＣＡＴＩＯＮＯＦＦＵＬＬＹＮＯＮＬＩＮＥＡＲＥＬＬＩＰＴＩＣＥＱＵＡＴＩＯＮＳＩＮＶＯＬＶＩＮＧＳＵＰＥＲ－ＣＲＩＴＩＣＡＬＳＯＢＯＬＥＶＥＸＰＯＮＥＮＴＳ￥ＱＵＣＨＡＮＧＺＨＥＮＧ（屈长征）（Ｉｎｓ...     

COMPERISON THEOREMS AND SUFFICIENT AND NECESSARY CONDITION FOR OSCILLATION OF FIRST ORDER NEUTRAL NONLINEAR DIFFERENTIAL EQUATIONS

ＣＯＭＰＥＲＩＳＯＮＴＨＥＯＲＥＭＳＡＮＤＳＵＦＦＩＣＩＥＮＴＡＮＤＮＥＣＥＳＳＡＲＹＣＯＮＤＩＴＩＯＮＦＯＲＯＳＣＩＬＬＡＴＩＯＮＯＦＦＩＲＳＴＯＲＤＥＲ　ＮＥＵＴＲＡＬＮＯＮＬＩＮＥＡＲＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＬｉＷａｎｔｏｎｇ...     

ON THE EXISTENCE AND UNIQUENESS THEOREMS OF SOLUTIONS FOR A CLASS OF THE SYSTEMS OF MIXED MONOTONE OPERATOR EQUATIONS WITH APPLICATION

ＯＮＴＨＥＥＸＩＳＴＥＮＣＥＡＮＤＵＮＩＱＵＥＮＥＳＳＴＨＥＯＲＥＭＳＯＦＳＯＬＵＴＩＯＮＳＦＯＲＡＣＬＡＳＳＯＦＴＨＥＳＹＳＴＥＭＳＯＦＭＩＸＥＤＭＯＮＯＴＯＮＥＯＰＥＲＡＴＯＲＥＱＵＡＴＩＯＮＳＷＩＴＨＡＰＰＬＩＣＡＴＩＯＮＳＨＥＮＰＥＩＬＯＮＧ...     

UNIQUENESS AND ITERATIVE METHOD OF POSITIVE RADIALLY SYMMETRIC SOLUTIONS FOR SINGULAR ELLIPTIC EQUATIONS

ＵＮＩＱＵＥＮＥＳＳＡＮＤＩＴＥＲＡＴＩＶＥＭＥＴＨＯＤＯＦＰＯＳＩＴＩＶＥＲＡＤＩＡＬＬＹＳＹＭＭＥＴＲＩＣＳＯＬＵＴＩＯＮＳＦＯＲＳＩＮＧＵＬＡＲＥＬＬＩＰＴＩＣＥＱＵＡＴＩＯＮＳ￥ＺｈａｏＺｅｎｇｑｉｎ（赵增勤）（ＱｕｆｕＮｏｒｍａｌＵｎｉｖｅ...     

普通型二分性与Favard定理

本文我们首先推广了著名的Ｆａｖａｒｄ定理并指出对齐次线性概周期系统由Ｆａｖａｒｄ定理所得到的概周期解是平凡的。然后利用推广后的Ｆａｖａｒｄ定理和普通型二分性讨论了一类线性和非线性系统的概周期解存在性。Ｎａｋａｊｉｍａ在文〔３〕中的结果是我们的结果的一种特殊情形。     

Analysis of the second order matrix Riccati equations

This paper is concerned with periodic solutions of 2x2 autonomous matrix Riccati differential equations. The author had given a necessary and sufficient condition for periodicity of solutions of matrix Riccati differential equations of general type and some examples. However, it is not so simple to verify whether this condition is satisfied or not. So this paper simplifies the verification by restricting to special cases. In particular, we show that there may exist periodic solutions for any case where the coefficient matrix of the linear part of the equation has complex eigenvalues if we choose an initial value suitably. Many examples having a periodic solution are also shown by systematic analysis; such examples are seldom seen in the literature.     

Almost Periodically Distributed Solutions for Diffusion Equations in Duals of Nuclear Spaces

We discuss the problem of the existence of almost periodic in distribution solutions of nuclear space-valued diffusion equations with almost periodic coefficients. Under a dissipativity condition we prove that the translation of the unique mean square bounded solution is almost periodically distributed. Similar results hold in the affine case under mean square stability of the linear part of the equation if the nuclear space is a component of a special compatible family. Accepted 19 December 1996     

On periodic solutions of countable systems of linear and quasilinear difference equations with periodic coefficients

We present conditions for the existence of periodic solutions of linear difference equations with periodic coefficients in spaces of bounded number sequences. In the case where the generating linear equation has a unique periodic solution, we indicate sufficient conditions for the existence of a periodic solution of a quasilinear difference equation.     

SUBNORMAL SOLUTIONS OF DIFFERENTIAL EQUATIONS WITH PERIODIC COEFFICIENTS

In this article, we apply the concept of hyper-order to higher order linear differential equations with periodic coefficients, investigate the existence and the form of its subnormal solution, and estimate the growth of all other solutions, and answer the question raised by Gundersen and Steinbart for more general periodic differential equations.     

On Periodic Solutions of Second Order Linear Difference Equations

In this paper, we apply a new procedure initially developed in Refs. [H. El-Owaidy and H.Y. Mohamed. "On the periodic solutions for nth order difference equations". Journal of Applied Mathematics and Computation , (to appear); "The necessary and sufficient conditions of existence of periodic solutions of nonautonomous difference equations". Journal of Applied Mathematics and Computation , (to appear)] to simplify the use of Carvalho's method to the case of discrete difference equations, in order to find the periodic solutions of second order linear difference equations. We can also find the complex periodic solutions.     

The Stability Analysis of the Periodic Traveling Wave Solutions of the mKdV Equation

The stability of periodic solutions of partial differential equations has been an area of increasing interest in the last decade. In this paper, we derive all periodic traveling wave solutions of the focusing and defocusing mKdV equations. We show that in the defocusing case all such solutions are orbitally stable with respect to subharmonic perturbations: perturbations that are periodic with period equal to an integer multiple of the period of the underlying solution. We do this by explicitly computing the spectrum and the corresponding eigenfunctions associated with the linear stability problem. Next, we bring into play different members of the mKdV hierarchy. Combining this with the spectral stability results allows for the construction of a Lyapunov function for the periodic traveling waves. Using the seminal results of Grillakis, Shatah, and Strauss, we are able to conclude orbital stability. In the focusing case, we show how instabilities arise.     

有积分算子的非线性发展方程的空间周期分叉解及其稳定性*

本文研究比较一般的有积分算子的非线性发展方程的空间周期分叉解及稳定性问题。首先分别研究分叉解存在的必要条件和充分条件,然后用算子半群方法分析平衡解的稳定性,并讨论了稳定性交换原则。最后研究一个应用例子,对有指数型积分算子的情形得到具体结果。     

Multibump solutions for discrete periodic nonlinear Schrödinger equations

In this paper, we study the existence of multibump solutions for discrete nonlinear Schrödinger equations with periodic potentials. We first reduce the existence of multibump homoclinic solutions to the existence of an isolated homoclinic solution with a nontrivial critical group. Then, we study the existence of homoclinics with nontrivial critical groups for both superlinear and asymptotically linear discrete periodic nonlinear Schrödinger equations, and we provide simple sufficient conditions for the existence of homoclinics with nontrivial critical groups in the positive definite case. As an application, we get, without any symmetry assumptions, infinitely many geometrically distinct homoclinic solutions with exponential decay at infinity.