相对映射的周期点

相对Nielsen周期点理论是讨论形如f(X,A)→(X,A)映射的周期点个数估计问题,本文对已知的估计量给予统一的处理.利用这种方法,定义了两个新的Nielsen型数,NPn(f;X-A)和Nφn(f;X-A),它们分别是映射f在Cl(X-A)中的n周期点和最小周期为n的周期点个数的下界.     

线段连续自映射非游荡集的拓扑结构

<正> 令X为拓扑空间,f:X→X为连续映射.f的不动点集F(f),周期点集P(f),周期点的周期,以及非游荡点集Ω(f)定义如常(例如,参见文献[1]).令x∈X,集合{f~n(x):n=0,1,2,….}称为x的轨迹,并记作O(x,f);当x为f的周期点时,O(x,f)称为x的周期轨迹.记Ω(f)为具有无限轨迹的非游荡点的集合.y∈X称为x∈X     

关于一类具有n周期点映射的构造方法

Li-Yorkc 指出:区间连续自映射 f(x)若有一个3周期点,则对于任意 n,f(x)有 n 周期点.本文给出了具有 n 周期点一类映射的构造方法.     

一类连续体上连续映射的周期点

设X是个阶有限的遗传可分解可链连续体, f:X→X是X上的连续自映射, On(x,f)={fi(x):0≤i≤n)是f的一个返回轨道, inf(On(x,f))相似文献   

熵极小动力系统的复杂性

设X是一个紧致度量空间,f:X→X是一个连续映射,(X,f)是熵极小的.该文首先证明了f是强遍历的;另外,如果还假设X中存在f的一个真的(拟)弱几乎周期点,则得到f具有正拓扑熵且对任意的n1,f~n是遍历敏感依赖的.因此,f在Li-Yorke和Takens-Ruelle意义下是混沌的.该文所得结论改进和推广了最近的一些结论.     

关于一类自映射轨道的研究

1 概念及已有结果 设X为拓扑空间,f∈C0（X,X）,f0表示恒等映射,对任意自然数n,定义fn=fοfn-1. 称O（x,f）={fn（x）│n=0,1,2,… ;x∈X}为x的f轨道. 关于周期点、周期点集、周期、周期轨道,Sarkovskii序如通常定义,可参见[1].     

周期吸附系统的分布混沌

由一个紧致度量空间X以及连续映射f:X→X所组成的偶对(X,f)称之为一个动力系统.若存在f的不动点p以及另一周期点q,使得对于任一非空开集U(?)X,都有∪_(n=0)~∞f~n(U)含有p和q,则称(X,f)是一个周期吸附系统,其中f~i表示f的i次迭代.本文指出:若(X,f)是一个周期吸附系统并且X是自密的,则存在一个f的分布混沌集D,使得D与每一非空开集之交都包含着一个Cantor集.     

拟线性系统的概周期解的存在性

<正> 考虑拟线性微分方程系 dX/dt=A(t)X十f(t)十μF(X,t,μ),(1)其中A(t)是t的n阶连续方阵,x是n向量,f(t),F(X,t,μ)是各变量的n连续向量,μ真是小参数. 当A(t)是常数方阵,f(t),F(X,t,μ)是t的一致概周期向量函数,Coddington,Levinson,等人建立了(1)的周期解的存在定理.此可参考[1]和[2].对A(t)为常数方阵,f(t),F(X,t,μ)是t的一致概周期向量函数,更进一步建立了(1)的概周期解的存在定理.     

附贴空间的度量化

<正> 设X与Y是互不相交的拓扑空间,A是X的闭集,f:A→Y是连续映射(简称映射).在X与Y的拓扑并W=XUY中,将A中点x与Y中的点f(x)叠合得到W的一个商空间Z,它就称作借助映射f:A→Y将X附贴到Y上的附贴空间(adjunction space);Z常更明确地表作XU_(f.A)Y.空间W至Z的商映射常记作p.易见p在Y上限制给出了     

一种点熵的估计与计算

对紧度量空间X上的连续自映射f：X→X，Hurley利用一点逆像的(n，ε)，分离子集，引入了熵hp(f)和hm(f)。按照拓扑熵观点，它们也度量了系统(X，f)的复杂性，本文将以Nielsen根类理论为工具，首先给出hp(f)的一个恰当的下界估计；然后作为该结果的应用，我们具体计算了环面上一类自映射的熵hp(f)，同时得到了该空间上自映射同伦类熵的一个下界估计。     

Day范数的c0（Γ,Χ）的暴露点和光滑点

设Γ为非空集,Ｘ为实Ｂａｎａｃｈ空间,本研究赋Ｄａｙ范数的ｃ０（Γ,Ｘ）的光滑点,强光滑点,暴露点和强暴露点。     

Renormings concerning exposed points and non-smoothness

Intuitively, non-smooth points might look like exposed points. However, in this paper we show that real Banach spaces having dimension greater than or equal to three can be equivalently renormed to obtain non-smooth points which are also non-exposed.     

Properties of symmetric matrices

We find the extreme points and the smooth points of the unit ball of the Banach space n_℘ of all real symmetric (n×n)-matrices.     

THE SUPPORT POINTS AND EXTREME POINTS OF THE UNIT BALL OF H'p

Byσthe author denotes the areal measure on the unit disk D=z: |z|<1. Let H'p={f(z): f(z) is analytic in D and 1/π∫D|f(z)|p dσ<+∞}. Let B(H＇p)={f:f∈H＇p and 1/π∫D|f(z)|p dσ1. This article researches the support points and extreme points of B(H'p).     

A short note about exposed points in real banach spaces

We express the set of exposed points in terms of rotund points and non-smooth points.As long as we have Banach spaces each time＂bigger＂,we consider sets of non-smooth points each time＂smaller＂.     

Recurrent points and non-wandering points of graph maps

Let G be a graph and f:G→G be a continuous map. Denote by P(f), R(f) and Ω(f) the sets of periodic points, recurrent points and non-wandering points of f, respectively. In this paper we show that: (1) If L=(x,y) is an open arc contained in an edge of G such that {fm(x),fk(y)}⊂(x,y) for some m,k∈N, then R(f)∩(x,y)≠∅; (2) Any isolated point of P(f) is also an isolated point of Ω(f); (3) If x∈Ω(f)−Ω(fn) for some n∈N, then x is an eventually periodic point. These generalize the corresponding results in W. Huang and X. Ye (2001) [9] and J. Xiong (1983, 1986) [17] and [19] on interval maps or tree maps.     

关于迭代函数不动点的研究

In this paper the following results are got 1. We prove that the order definitionwhich is given by J.F. Trawb on the iterative function is wrong. 2. A existent theorem on the repulsive point is given. 3. We give some theorems to judge a fixed point of iterative function. They all imporve the Ostrowski's theorems.     

星形函数族的一个子族的极值点与支撑点

设T={f(z):f(z)在单位圆盘|z|<1上解析,f(z)=z ,an是实数, |an|≥|an 1|且|an|≤1}．该文找出了解析函数族T的极值点与支撑点.     

On the number of triple points of an immersed surface with boundary

Given a generic immersionf:S ¹→S ² of a circle into the sphere, we find the best possible lower estimation for the number of triple points of a generic immersionF: (M, S ¹)→(B ³,S ²) extendingf, whereM is an oriented surface with boundary ∂M=S ¹,B ³ is the 3-dimensional ball with boundaryS ². Supported by the Hungarian National Science and Research Foundation OTKA 2505 Supported by the Hungarian National Science and Research Foundation OTKA T4232 This article was processed by the author using the Springer-Verlag T_EX P Jour1g macro package 1991.     

Extreme points, exposed points, differentiability points in CL-spaces

This paper presents a property of geometric and topological nature of Gateaux differentiability points and Fréchet differentiability points of almost CL-spaces. More precisely, if we denote by a maximal convex set of the unit sphere of a CL-space , and by the cone generated by , then all Gateaux differentiability points of are just n-s, and all Fréchet differentiability points of are (where n-s denotes the non-support points set of ).