一类平面三次拟齐次向量场的全局拓扑结构

利用中心投影变换的思想证明一类平面三次拟齐次向量场的几何性质依赖于它的切向量场和诱导向量场.讨论了该系统的拓扑结构,并进行了分类;证明了该系统具有25类不同类的拓扑结构相图.     

一类带有三次项的平面五次微分系统的全局拓扑结构分析

一类带有三次项的平面五次微分系统在Poincare变换下可以讨论系统的无穷远奇点的性质,进而得到奇点附近轨线的拓扑结构,并利用判断函数给出极限环存在与否的条件,补充完善了五次系统的定性分析.     

一类具有星形结点的平面四次多项式系统的全局结构及其实例

主要讨论一类具有星形结点的平面四次多项式微分系统的全局结构,用系统的积分直线把相平面分成四类扇形区域,根据系统的有限远奇点的情况,给出了相应的实例及其全局结构。     

具有星形结点的平面五次系统的全局结构分析

该文对具有星形结点的平面五次系统的全局结构的拓扑分类应用Ⅰ Ⅳ型区域(见［2］),讨 论了平面五次系统（1）的全局结构的拓扑分类，并得到93种全局结构及其右边多项式系统的判定方法。      

一类齐三次系统的全局结构

本文讨论了一类齐三次系统的全局结构，并给出了它们的系数条件．     

具有六对特殊方向的一类平面齐五次系统的全局拓扑结构

In this paper,a class of plane homogeneous fifth system with six special direction is studied,and the global topological classification and coefficient conditions is discussed.     

一类平面奇次系统的全局结构

通过研究一类平面奇次系统的有限远奇点和无穷远奇点的类型,对其进行定性分析,得到系统的全局结构及其相图.     

具有三对特殊方向的一类平面齐五次系统的全局拓扑结构

研究了一类平面齐五次系统dxdxdt=a50x5+a41x4y+a32x3y2+a23x2y3+a14xy4+a05y5,dydt=b50x5+b41x4y+b32x3y2+b23x2y3+b14xy4+b05y5当其只有唯一的有限远奇点且具有三对特殊方向时的全局拓扑结构及系数条件.假设系统只有唯一的有限远奇点(0,0),不妨设b50=0,其特殊方向由示性方程G(θ)=0给出,引进poincare变换研究无穷远奇点,再根据定理中的系数条件,列出系统所有可能的无穷远奇点和特殊方向,并判断其类型,由此画出系统具有三对特殊方向时的全局相图.     

具有五对特殊方向的一类平面齐五次系统的全局拓扑结构

研究了一类具有五对特殊方向的平面齐五次系统的全局拓扑分类及系数条件.     

全局拓扑线性化理论的推广

微分方程dx/dt=Ax f(x)(其中A的特征根实部异于零)拓扑线性化的经典结论是由Hartman与 Grobman给出的,但是他们的结论都是局部拓扑线性化,即要求同胚函数限制在原点的小邻域内．如 果要延伸到全局上的话,必须f(x)有界．本文研究了系统(1．3),证明当此系统满足适当的条件时可全 局线性化．     

The Closed Orbits of a Class of Cubic Vector Fields in R3

In this paper, we investigate the isolated closed orbits of two types of cubic vector fields in R₃ by using the idea of central projection transformation, which sets up a bridge connecting the vector field X(x) in R₃ with the planar vector fields. We have proved that the cubic vector field in R₃ can have two isolated closed orbits or one closed orbit on the invariant cone. As an application of this result, we have shown that a class of 3-dimensional cubic system has at least 10 isolated closed orbits located on 5 invariant cones, and another type of 3-dimensional cubic system has at least 26 isolated closed orbits located on 13 invariant cones or 26 invariant cones.     

Global Topological Linearization with Unbounded Nonlinear Term

§ 1.Statementof Theorem　 Consider the systemx′=Ax + f (x) ,y′=By +φ(x) +ψ(y) ,(1 )where x∈ Rn1,y∈ Rn2 ,f,φ andψ are locally Lipschitzian.If x is in Rn we denote itsEnclidend norm by| x| and if A is an n×n matrix we denote its operator norm by| A| .Let Reλ(A) be the real partof eigenvalues of A.　 Suppose that Reλ(A) <0 and Reλ(B) >0 .Without loss of generality,we may assamethatd| x| 2dtx′=Ax≤ -α| x| 2 , (2 )| e- Bt|≤ k . e-βt　 (t≥ 0 ) , (3 )whereα,β and k are all…     

A Global Geometric Decomposition of Vector Fields and Applications to Topological Conjugacy

We give a global geometric decomposition of continuously differentiable vector fields on \(\mathbb{R}^{n}\). More precisely, given a vector field of class \(\mathcal{C}^{1}\) on \(\mathbb{R}^{n}\), and a geometric structure on \(\mathbb{R}^{n}\), we provide a unique global decomposition of the vector field as the sum of a left (right) gradient-like vector field (naturally associated to the geometric structure) with potential function vanishing at the origin, and a vector field which is left (right) orthogonal to the Euler vector field, with respect to the geometric structure. As application, we provide a criterion to decide topological conjugacy of complete vector fields of class \(\mathcal{C} ^{1}\) on \(\mathbb{R}^{n}\) based on topological conjugacy of the corresponding parts given by the associated geometric decompositions.

     

Bifurcation and Isochronicity at Infinity in a Class of Cubic Polynomial Vector Fields

In this paper, we study the appearance of limit cycles from the equator and isochronicity of infinity in polynomial vector fields with no singular points at infinity. We give a recursive formula to compute the singular point quantities of a class of cubic polynomial systems, which is used to calculate the first seven singular point quantities. Further, we prove that such a cubic vector field can have maximal seven limit cycles in the neighborhood of infinity. We actually and construct a system that has seven limit cycles. The positions of these limit cycles can be given exactly without constructing the Poincare cycle fields. The technique employed in this work is essentially different from the previously widely used ones. Finally, the isochronous center conditions at infinity are given.     

具有Hamilton结构的反应扩散方程组的整体吸引子

本文研究了具有Hanmilton结构的反应扩散方程组,证明其存在不变区域及吸引集,再证明其整体吸引子的存在性。     

一个具有Hamilton结构的反应扩散系统的空间离散化整体吸引子（英）

In recent years there has been a growing interest on discrete models, see e.g.[1].[2].We consider a reaction diffusion equation which space-independent system is a Hamilton system with one degree of freedom:     

一类非线性金融系统分岔混沌拓扑结构与全局复杂性研究（Ⅱ）

首先从一类复杂金融系统的数学模型出发,在前期研究工作的基础上,主要研究这一模型所反映的我国宏观金融系统运行中可能出现的各种情况：平衡、稳定周期、分形、Hopf分岔、参数与Hopf分岔之间的关系;直到混沌运动等,通过理论分析和数值模拟计算来研究模型中各参数的变化情况,然后依此来分析这类金融系统局部产生复杂行为的条件,以及某一参数的变化对宏观经济政策的调整及对整个金融系统行为的影响情况,这一研究将有助于加深人们对各种金融政策杠杆作用的理解。