一类高维非自治Volterra系统的周期解

本文用矩阵测度和不动点定理对一类高维非自治 Volterra系统的周期解进行了讨论 ,给出了存在唯一稳定周期解的判别准则 ,避免了构造 Lyapunov函数的困难 ,推广了文 [2 ]的工作 .     

用试验数据修正振动系统的双对称阻尼矩阵与刚度矩阵

讨论用试验数据修正振动系统的双对称阻尼矩阵与刚度矩阵问题.依据特征方程、阻尼矩阵与刚度矩阵的双对称性,利用代数二次特征值反问题的理论和方法,研究了该问题解的存在性与唯一性,提出了修正阻尼矩阵与刚度矩阵的一个新方法.利用双对称矩阵的性质研究了方程的双对称解.给出了二次特征值反问题双对称解的一般表达式,讨论了对任意给定矩阵的最佳逼近问题,并给出了问题的最佳逼近解.用该方法修正的阻尼矩阵与刚度矩阵不仅满足二次特征方程,而且是唯一的双对称矩阵.     

反中心对称矩阵反问题解存在的条件

讨论了反中心对称矩阵反问题及其最佳逼近。研究了矩阵反问题有解的充分和必要条件,利用这类矩阵的结构和特征性质得到了矩阵反问题解的通式;证明了最佳逼近问题存在唯一解,并给出了求最佳逼近解的算法和数值算例。     

具有无穷时滞泛函微分方程的周期解

讨论具有无穷时滞中立型泛函微分方程的周期解问题.利用矩阵测度和Krasnoselskii不动点定理得到了周期解的存在性和唯一性定理;特别地,当Q（s）为零矩阵,A（t,x）=A（t）时给出了存在唯一稳定的周期解的条件.     

子矩阵约束下的Hermite-Hamilton矩阵反问题

该文讨论了子矩阵约束下矩阵反问题$AX=B$的Hermite-Hamilton矩阵解.给出了解存在的充要条件和通解的一般表达式.且对任一给定矩阵,在解集合中求出了其最佳逼近解.     

求解子矩阵约束条件下四元数矩阵方程AXB=C的矩阵半张量积方法

1引言子矩阵约束下的矩阵方程问题是指限定矩阵方程的解X的一个子矩阵X_(0),然后在某个约束集合中求解矩阵方程.如求满足X([1:q])=X_(0)的对称解,这里X([1:q])表示矩阵X的q阶顺序主子阵.子矩阵约束下的矩阵方程问题来源于实际中的系统扩张问题[1],有一定的实际意义和重要性,受到了许多学者的关注,如[2-4]中,彭分别研究了子矩阵约束条件下实矩阵方程AX=B的实矩阵解,中心对称解和双对称解.     

一类广义Sylvester方程的反对称最小二乘解及其最佳逼近

本文利用矩阵的奇异值分解(SVD),给出了广义Sylvester矩阵方程AX YA=C反对称解存在的充分必要条件,导出了其反对称解和反对称最小二乘解的表达式,同时在解集合中得到了对给定矩阵的最佳逼近解.     

一类线性随机H∞控制问题的Riccati矩阵微分方程

讨论了一类线性随机H∞控制问题的解的存在性和相关的Riccati矩阵微分方程的迭代解法.建立了一个算法,利用李雅普诺夫线性矩阵微分方程的解,一致逼近Riccati矩阵微分方程的解.     

一类高维非自治Volterra系统的周期解

本用矩阵测度和不动点定理对一类高维非自治Volterra系统的周期解进行了讨论,给出了存在唯一稳定周期的判断准则,避免了构造Lyapunov函数的困难,推广了[2]的工作。     

一类对称正交反对称矩阵反问题的最佳逼近

讨论了一类对称正交反对称反问题的最佳逼近.利用对称正交反对称矩阵的特殊性质,给出了矩阵方程AX=B有对称正交反对称解的充要条件以及解的一般表达式;证明最佳逼近解的存在惟一性并给出其表达式;最后给出计算任意矩阵的最佳逼近解的数值方法及算例.     

Homographic Solutions of the N -body Generalized Lennard-Jones System

In this paper,we obtain the existence of non-planar circular homographic solutions and non-circular homographic solutions of the(2+N)-and(3+N)-body problems of the Lennard-Jones system.These results show the essential difference between the Lennard-Jones potential and the Newton's potential of universal gravitation.     

Periodic solutions of the N-body problem

This paper proves the existence of six new classes of periodic solutions to the N-body problem by small parameter methods. Three different methods of introducing a small parameter are considered and an appropriate method of scaling the Hamiltonian is given for each method. The small parameter is either one of the masses, the distance between a pair of particles or the reciprocal of the distances between one particle and the center of mass of the remaining particles. For each case symmetric and non-symmetric periodic solutions are established. For every relative equilibrium solution of the (N ? 1)-body problem each of the six results gives periodic solutions of the N-body problem. Under additional mild non-resonance conditions the results are roughly as follows. Any non-degenerate periodic solutions of the restricted N-body problem can be continued into the full N-body problem. There exist periodic solutions of the N-body problem, where N ? 2 particles and the center of mass of the remaining pair move approximately on a solution of relative equilibrium and the pair move approximately on a small circular orbit of the two-body problems around their center of mass. There exist periodic solutions of the N-body problem, where one small particle and the center of mass of the remaining N ? 1 particles move approximately on a large circular orbit of the two body problems and the remaining N ? 1 bodies move approximately on a solution of relative equilibrium about their center of mass. There are three similar results on the existence of symmetric periodic solutions.     

Infinitely Many Noncollision Periodic Solutions for Planar Keplerian-Like 2-Body Problems

Using the implicit rotational invariant property for the potential and the variational functional, we prove the existence of infinitely many noncollision periodic solutions for planar Keplerian-like 2-body problems.AMS Mathematics Subject Classification: 34C15, 34C25, 58F, 70F10     

一类具周期系数的Riccati型方程的周期解

给出 Riccati型方程x=A( t) x2 m+B( t) x2 k- 1 +C( t)( A( t) ,B( t) ,C( t)是周期为 T的连续函数 ,m,k∈ N且 m≥ k)无周期解及存在周期解的充分条件 .     

二阶离散周期边值问题的多重正解

考虑如下边界值问题:-Δ[p(n-1)Δy(n-1)]+q(n)y(n)=f(n,y(n)),n∈[1,N](1.1)y(0)=y(N),p(0)Δy(0)=p(N)Δy(N)(1.2)其中{y(n)}nN=+01是一个期望解.运用锥不动点定理,给出了一种二阶离散周期边值问题多重正解的新的存在性定理.     

Super Riemann theta function periodic wave solutions and rational characteristics for a supersymmetric KdV-Burgers equation

Using a multidimensional super Riemann theta function, we propose two key theorems for explicitly constructing multiperiodic super Riemann theta function periodic wave solutions of supersymmetric equations in the superspace ℝ _Λ^N+1,M, which is a lucid and direct generalization of the super-Hirota-Riemann method. Once a supersymmetric equation is written in a bilinear form, its super Riemann theta function periodic wave solutions can be directly obtained by using our two theorems. As an application, we present a supersymmetric Korteweg-de Vries-Burgers equation. We study the limit procedure in detail and rigorously establish the asymptotic behavior of the multiperiodic waves and the relations between periodic wave solutions and soliton solutions. Moreover, we find that in contrast to the purely bosonic case, an interesting phenomenon occurs among the super Riemann theta function periodic waves in the presence of the Grassmann variable. The super Riemann theta function periodic waves are symmetric about the band but collapse along with the band. Furthermore, the results can be extended to the case N > 2; here, we only consider an existence condition for an N-periodic wave solution of a general supersymmetric equation.     

On the existence of infinitely many periodic solutions to some problems of n-body type

We prove the existence of infinitely many periodic solutions with prescribed period to a class of problems of n-body type.     

Bifurcations of travelling wave solutions for the generalized (2+1)-dimensional Boussinesq-Kadomtsev-Petviashvili equation

By using the bifurcation theory of dynamical systems, we study the generalized (2+1)-dimensional Boussinesq-Kadomtsev-Petviashvili equation, the existence of solitary wave solutions, compacton solutions, periodic cusp wave solutions and uncountably infinite many smooth periodic wave solutions are obtained. Under different parametric conditions, various sufficient conditions to guarantee the existence of the above solutions are given. Some exact explicit parametric representations of the above waves are determined.     

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.     

Some new nonlinear wave solutions and their convergence for the (2+1)‐dimensional Broer–Kau–Kupershmidt equation

We use the bifurcation method of dynamical systems to study the (2+1)‐dimensional Broer–Kau–Kupershmidt equation. We obtain some new nonlinear wave solutions, which contain solitary wave solutions, blow‐up wave solutions, periodic smooth wave solutions, periodic blow‐up wave solutions, and kink wave solutions. When the initial value vary, we also show the convergence of certain solutions, such as the solitary wave solutions converge to the kink wave solutions and the periodic blow‐up wave solutions converge to the solitary wave solutions. Copyright © 2014 John Wiley & Sons, Ltd.