关于非自治动力系统中的h-极小覆盖

设（X,d1,f1∞）与（Y ,d2,g1,∞）为两个非自治动力系统,h是从（X,d1,f．∞）到（Y,d2,g1∞）的拓扑半共轭．通过对自治动力系统中的h一极小覆盖的研究,本文得到了以下结论：1）对于任意的Y∈Y及X∈h-1（y）,orb（x,f1∞）被h映射为orb（y,g1∞）,w（x,f1∞）被h映射为w（y,g1∞）;2）在（X,d1,f1∞）中引入关于拓扑半共轭的h-极小覆盖的定义,证明了h一极小覆盖的存在性;3）对于任意的XEX和Y∈Y,在（w（z,f1∞）,f1∞。（x,f1,∞）与（w（y,g∞）,g1,∞（y,g1∞））均构成原系统的子系统的前提下,R（f1∞）被h映射为R（g1∞）．这些结论丰富了非自治动力系统的内容．     

线性拓扑空间中向量凸规划的鞍点定理

设X为实向量空间,Y与Z为实线性拓扑空间,Z有局部凸性质,P_Y和P_Z是Y与Z的实心闭凸锥,P_Y≠Y,P_Z≠Z.由P_Y和P_Z分别在Y和Z中诱导的半序记为≤. Y和Z的共轭空间,即各自上面的连续线性泛函的全体,记为Y~*和Z~*. P_Y和P_Z的共轭锥记为P_Y~*和P_Z~*.设f:X→Y,g:X→Z都是关于上述半序的凸映身     

两个空间之间复合映射的不动点集和Reidemeister数

设X,Y为拓扑空间,f:X→Y,g:y→X．该文证明了下列结论:对每一自然数n, (1)f(Fix((g o,f)n))=Fix((f o g)n),g(Fix((f og )n))=Fix(g o f)n),且#Fix((g o f)n)= #Fix((f o g)n);(2)R((g o f)n)=R((f o g)n)．     

保持谱半径的乘法映射

设X和Y为无限维Banach空间,Φ：B（X）→B（Y）是保持谱半径的满射,且秩为1算子,则Φ具有形式Φ（T）=ATA∧-1,这里A：X→Y或是线性拓扑同构映射或是线性拓扑同构映射的共轭。     

两个空间之间复合映射的不动点集和Reidemeister数

设X,Y为拓扑空间,f:X--> Y, g:Y--> X.该文证明了下列结论：对每一自然数n,(1)f(Fix((g f)^n))=Fix((f g)^n), g(Fix((f g)^n))=Fix((g f)^n),且#Fix((g f)^n)=#Fix((f g)^n);(2)R((g f)^n)=R((f g)^n).     

关于 Heine 定理成立的两个充分条件

本文论述拓扑空间 X 具有 A_1(即 X 满足第一可数公理)和 X 的拓扑能用列收敛刻划(即 (?)A(?)X 及(?)a∈(?),A 中有序列 x_n→x)各自分别是映射 f:X→Y(Y 也是拓扑空间)具有 Heine 性质(即 f:X→Y 连续(?)(?)x∈X 及 X 中的任何序列{x_n},由 x_n→x 可推出f(x_n)→f(x))的充分条件,但都非必要条件,而且后一个条件弱于前一个条件.     

关于LF拓扑中的两个未解决问题

证明了：⑴LF序列空间（L^X,δ）到LF拓扑空间（L^Y1,μ）的序同态f在e∈M*(L^X)处连续当且仅当对（L^X,δ）中每个收敛于e的分子序列S，f(S)在（L^Y1,μ）中皆收敛于f(e)；⑵若一族LF拓扑空间的积空间的特征≤m，则每个满层的因子空间的特征≤m,从而我们解决了[1]中提出的两个未解决问题。     

部分临界点轨道收敛于无穷大时的多项式动力系统

设Ｐ（ｚ）是ｄ（≥２）次多项式，Ｊ是Ｐ（ｚ）的Ｊｕｌｉａ集，σ：∑ｎ→∑ｎ是ｎ个符号的单边符号空间∑ｎ上的转移自映射．本文证明了当ｐ（ｚ）的某ｍ（１≤ｍ≤ｄ－１）个有穷临界点的轨道收敛于∞时，ｐ｜Ｊ拓扑半共轭于σ：∑（ｍ＋１）→∑（ｍ＋１），而当ｍ＝ｄ－１时，ｐ｜Ｊ拓扑共轭于σ：∑ｄ→∑ｄ。     

拓扑遍历与拓扑双重遍历

令X为紧致度量空间,f:X→X为连续映射,U,V为X的任意非空开集,若{n>0|fn(U)∩V≠ )为正上密度集,则称f拓扑遍历.f拓扑双重遍历意味着f×f拓扑遍历.本文在[2]的基础上进一步讨论拓扑遍历与拓扑双重遍历映射的性质.     

［X→L］上的Isbell拓扑和Scott拓扑

本文证明了：对ｃｏｒｅｃｏｍｐａｃｔ空间Ｘ和具有最小元的有界完备连续ＤＣＰＯＬ，［Ｘ→Ｌ］上的Ｉｓｂｅｌｌ拓扑与Ｓｃｏｔｔ拓扑重合．并且构造两个反例说明：若Ｌ不具有最小元，或Ｌ具有最小元但不满足有界完备性，则［Ｘ→Ｌ］上的Ｉｓｂｅｌｌ拓扑与Ｓｃｏｔｔ拓扑不必重合．     

Some remarks on foliatedS 1 bundles

Summary Every two homomorphisms from the fundamental group of an oriented closed surface of genus 2 into the group of orientation preserving homeomorphisms (resp.C ² diffeomorphisms) of the circle are shown to be mutually semi-conjugate (resp. topologically conjugate), provided their Euler numbers attain the minimal value (or the maximal value) allowed by the Milnor-Wood inequality.     

Topological collapsings and cylindrical neighborhoods in 3-manifolds

We introduce the concept of topological collapsing as a topological abstraction of polyhedral ones. Then we use this concept to characterize the cylindrical neighborhoods of a closed X in a locally compact separable metric space M such that M - X is a 3-manifold. We also prove the following criterion of existence: X has cylindrical neighborhoods in M iff there is a neighborhood N of X in M which is topologically collapsible onto X respecting Bd(M - X).     

A topological horseshoe in a fractional-order Qi four-wing chaotic system

A fractional-order Qi four-wing chaotic system is present based on the Grunwald-Letnikov denition. The existence of topological horseshoe in a fractional chaotic system is analyzed by utilizing topological horseshoe theory. A Poincare section is properly chosen to obtain the Poincare map which is proved to be semi-conjugate to a 2-shift map, implying that the fractional-order Qi four-wing chaotic system exhibits chaos.     

Topologically conjugate Kleinian groups

Two Kleinian groups and are said to be topologically conjugate when there is a homeomorphism such that . It is conjectured that if two Kleinian groups and are topologically conjugate, one is a quasi-conformal deformation of the other. In this paper generalizing Minsky's result, we shall prove that this conjecture is true when is finitely generated and freely indecomposable, and the injectivity radii of all points of and are bounded below by a positive constant.

     

不含混沌真子系统的Li-Yorke混沌

研究了一类Li-Yorke混沌系统,该系统没有真子系统是Li-Yorke混沌的,我们称之为混沌极小系统.本文证明混沌极小系统是拓扑传递的,而且该系统每个非空开集都包含一个不可数混乱集.混沌极小系统不一定是极小的,本文构造了一个这样的反例.特别地,我们考察了线段连续自映射,指出该类系统都不是混沌极小的,线段上混沌极小子系统的存在性和该系统有正熵是等价的.     

Robust transitivity and topological mixing for -flows

We prove that nontrivial homoclinic classes of -generic flows are topologically mixing. This implies that given , a nontrivial -robustly transitive set of a vector field , there is a -perturbation of such that the continuation of is a topologically mixing set for . In particular, robustly transitive flows become topologically mixing after -perturbations. These results generalize a theorem by Bowen on the basic sets of generic Axiom A flows. We also show that the set of flows whose nontrivial homoclinic classes are topologically mixing is not open and dense, in general.

     

Further discussion on Kato""s chaos in set-valued discrete systems

For a compact metric space $Y$ and a continuous map $g:Y\rightarrow Y$, the collective accessibility and collectively Kato chaotic of the dynamical system $(Y, g)$ were defined. The relations between topologically weakly mixing and collective accessibility, or strong accessibility, or strongly Kato chaos were studied. Some common properties of $g$ and $\overline{g}$ were given. Where $\overline{g}: \kappa(Y)\rightarrow \kappa(Y)$ is defined as $\overline{g}(B)=g(B)$ for any $B\in\kappa(Y)$, and $\kappa(Y)$ is the collection of all nonempty compact subsets of $Y$. Moreover, it is proved that $g$ is collectively accessible (or strongly accessible) if and only if $\overline{g}$ in $w^{e}$-topology is collectively accessible (or strongly accessible).     

A Devaney Chaotic System Which Is Neither Distributively nor Topologically Chaotic

Weiss proved that Devaney chaos does not imply topological chaos and Oprocha pointed out that Devaney chaos does not imply distributional chaos. In this paper, by constructing a simple example which is Devaney chaotic but neither distributively nor topologically chaotic, we give a unified proof for the results of Weiss and Oprocha.     

CHAOS AND TOPOLOGICAL MIXING OF TREE MAPS

In the present paper we show that a tree map is totally transitive iff it is topologically mixing. Using this result, we prove that the tree maps having a chaotic (or scrambled) subset with full Lebesgue measure is dense in the space consisting of all topologically mixing (transitive, respectively) maps.     

Chaos in a topologically transitive system

The chaotic phenomena have been studied in a topologically transitive system and it has been shown that the erratic time dependence of orbits in such a topologically transitive system is more complicated than what described by the well-known technology "Li-Yorke chaos". The concept "sensitive dependency on initial conditions" has been generalized, and the chaotic phenomena has been discussed for transitive systems with the generalized sensitive dependency property.