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1.
弱拓扑和强可容许拓扑之间的一个关系   总被引:2,自引:0,他引:2  
孙立民 《数学杂志》2003,23(2):141-145
本文对局部凸空间X及其对偶X′,建立了弱拓扑σ(X,X′)和强拓扑β(X,X′)之间的一个新关系,改进了有关(X,X′)--可容许拓扑全体上的不变性结果。  相似文献   

2.
本文给出具有散子代数的BCI代数的条件,讨论了L(X)为X的理想的BCI代数,完全刻划了每个子代数都是理想的BCI代数。  相似文献   

3.
Siberian Mathematical Journal - Let X be a Banach space and let T: X → X be a linear power bounded operator. Put X 0 = {x ∈ X | T n x → 0}. We prove that if X 0 ≠ X then...  相似文献   

4.
一类广义变换半群的格林关系   总被引:1,自引:0,他引:1  
设X是一个全序集,E是X上的一个凸等价关系.令 OE(X)={f∈TE(X):Ax,y∈X,x≤y→f(x)≤f(y)), 其中TE(X)是E-保持变换半群.对于取定的θ∈OE(X),在OE(X)上定义运算fog=fθg,使OE(X)成为广义半群OE(X;θ).对于有限全序集X上的凸等价关系E,本文刻画了广义半群OE(X;θ)的正则元,描述了这个半群的格林关系.  相似文献   

5.
侯吉成 《数学进展》2002,31(3):271-274
设X是拓扑空间,CL(X)表示X的所有非空闭子集的族,本文得到了下述结果:在CL(X)上的Fell-拓扑是伪肾的当且仅当X是feebly-紧或者非局部紧或者非σ-紧,由此得到了对于伪紧性不是闭遗传的两类新的拓扑空间。  相似文献   

6.
We prove that a locally compact ANR-space X is a Q-manifold if and only if it has the Disjoint Disk Property (DDP), all points of X are homological Z∞-points and X has the countable-dimensional approximation property (cd-AP), which means that each map f:K→X of a compact polyhedron can be approximated by a map with the countable-dimensional image. As an application we prove that a space X with DDP and cd-AP is a Q-manifold if some finite power of X is a Q-manifold. If some finite power of a space X with cd-AP is a Q-manifold, then X2 and X×[0,1] are Q-manifolds as well. We construct a countable familyχof spaces with DDP and cd-AP such that no space X∈χis homeomorphic to the Hilbert cube Q whereas the product X×Y of any different spaces X, Y∈χis homeomorphic to Q. We also show that no uncountable familyχwith such properties exists.  相似文献   

7.
在林寿与我最近合作的一篇文章中指出了∑*-空间的构成定理需重新考虑.本文就是要证明在空间X的每个点是Gδ-集的条件下该构成定理是成立的,所得的结论是:X是T1且每个点是Gδ-集的∑*-空间,如果f:X→Y是闭的满连续映射,则在Y中有一σ-闭离散子空间Z,使得对每个y∈Y\Z,f-1(y)是X的w1-紧子空间.为得到该主要结果,本文证明了若空间X是每个点是Gδ-集的次亚紧空间.则X中的每个闭离散子集是X中的Gδ-集.  相似文献   

8.
设x是简单无向图,G是Aut(X)的一个于群,X称为G-对称的,如果G在x的1-孤(即两相邻顶点构成的有序偶)集合上的作用是传递的;x称为对称图,如果X是Aut(x)-对称的;x称为可解对称的,如果Aut(X)包含可解子群G,使X是G-对称的.本文给出了具有6P个顶点的可解对称图的一个分类,这里p≥5是素数.  相似文献   

9.
假设S(X)是Banach空间X的单位球面,作引进了四个新的几何参数:Jε(X)=sup{βε(x),x∈S(X)},jε(X)=inf{βε(x),x∈S(X)},Gε(X)=sup{αε(x),x∈S(X)},gε(X)=inf{αε(x),x∈S(S)},其中≤ε≤1,βε(x)=sup{min{‖x εy‖,‖x-εy‖,y∈S(X)}},αε(x)=inf{max{‖x εy‖,‖x-εy‖,y∈S(X)}},讨论了这些参数的性质,本主要结果是:如果主要结果是:如果有一个ε,0≤ε≤1,使得Jε(X)<1 ε/2或gε(X)>1 ε/3,那末X有一至正规结构。  相似文献   

10.
Let Y be a subset of X and T(X, Y) the set of all functions from X into Y. Then, under the operation of composition, T(X, Y) is a subsemigroup of the full transformation semigroup T(X). Let E be an equivalence on X. Define a subsemigroup $$T_E(X,Y)$$ of T(X, Y) by $$\begin{aligned} T_E(X,Y)=\{\alpha \in T(X,Y):\forall (x,y)\in E, (x\alpha ,y\alpha )\in E\}. \end{aligned}$$Then $$T_E(X,Y)$$ is the semigroup of all continuous self-maps of the topological space X for which all E-classes form a basis carrying X into a subspace Y. In this paper, we give a necessary and sufficient condition for $$T_E(X,Y)$$ to be regular and characterize Green’s relations on $$T_E(X,Y)$$. Our work extends previous results found in the literature.  相似文献   

11.
设X为一个集合,■_X为X上的全变换半群.设E是X上的一个等价关系,定义T_E(X)={f∈■_X:■(x,y)∈E,(f(x),f(y))∈E},则T_E(X)是由等价关系E所确定的■_X的子半群.本文中,所考虑的集合X是一个有限全序集,同时E是非平凡的且所有的E-类都是凸集.显然■_E(X)={f∈T_E(X):■_x,y∈X,x≤y蕴涵f(x)≤f(y)}是T_E(X)的一个子半群.我们赋予■_E(X)自然偏序并讨论何时■_E(X)中的两个元素是关于这个偏序是相关的,然后确定■_E(X)中那些关于≤是相容的元素.此外,还描述了极大(极小)元和覆盖元.  相似文献   

12.
In this note,we present that:(1)Let X=σ{Xα:α∈A} be|A|-paracompact (resp.,hereditarily |A|-paracompact).If every finite subproduct of {Xα:α∈A} has property b1 (resp.,hereditarily property b1),then so is X.(2) Let X be a P-space and Y a metric space.Then,X×Y has property b1 iff X has property b1.(3) Let X be a strongly zero-dimensional and compact space.Then,X×Y has property b1 iff Y has property b1.  相似文献   

13.
Let X be a Kobayashi hyperbolic complex manifold, and assume that X does not contain compact complex submanifolds of positive dimension (e.g., X Stein). We shall prove the following generalization of Ritt’s theorem: every holomorphic self-map f:X→X such that f(X) is relatively compact in X has a unique fixed point τ(f) ∈ X, which is attracting. Furthermore, we shall prove that τ(f) depends holomorphically on f in a suitable sense, generalizing results by Heins, Joseph-Kwack and the second author.  相似文献   

14.
LI Yi-jun 《数学季刊》2006,21(2):196-201
To obtain a better Vinogradov's bound, assistant function with two or three zeros and all Dirichlet's characters has been evaluated. Assistant function g(X1,X2,X3,X4)with four zeros and all nonprincipal characters but X1X2X3X4 is constructed and evaluated in the paper. And the constant obtained is 8.395 511 841 994.  相似文献   

15.
廖山涛 《数学学报》1957,7(2):183-199
<正> 在§1我们界说了局部乘积,它关联 Hausdorff 紧致空间 X 中闭子集X_0的同调以及 X_0在 X 中邻域的同调.在流形与有边流形上的 Poincaré-Alexander-Lefschetz 型对偶定理可以用这种局部乘积表示(§2).在§3,我们研讨了一类所谓摹流形状空间.局部的下调群与上调群的概念在 [3,233—263页;8]中曾不明显地使  相似文献   

16.
The purpose of this work is to describe the (category of) Higgs bundles on a scheme X/C having a given cameral cover \bar{X}. We show that this category is a T \bar{X} gerbe, where T \bar{X} is a certain sheaf of abelian groups on X, and we describe the class of this gerbe precisely. In particular, it follows that the set of isomorphism classes of Higgs bundles with a fixed cameral cover \bar{X} is a torsor over the group H1(X, T \bar{X}) which itself parametrizes T \bar{X} torsors on X. This underlying group H1(X, T \bar{X}) can be described as a generalized Prym variety, whose connected component is either an abelian variety or a degenerate abelian variety. The main part of the work deals with abstract Higgs bundles; in the last two sections we derive the applications to Higgs bundles valued in a line bundle K and to bundles on elliptic fibrations.  相似文献   

17.
Let X be a limit space, Y a topological space. We show that c(X,Y), the limitierung of continuous convergence on LIM(X,Y), is topological whenever X is basic locally compact. For regular Y, local compactness of X is sufficient. In both cases, c(X,Y) coincides with the compact-open topology. If X satisfies a certain regularity condition, the fact that c(X,Y) is topological implies, conversely, that X is (basic) locally compact.The author would like to thank S. Weck for some inspiring discussions.  相似文献   

18.
Let X be a complex space and AcX an exceptional analytic set. Then there exists a coherent sheaf of ideals J on X with zero set A, such that the complex subspace of X defined by J has weakly negative normal bundle in X. As a consequence it is proven that every Moishezon space X carries a weakly positive coherent analytic sheaf with support X.  相似文献   

19.
极大前缀码的刻划   总被引:5,自引:3,他引:2  
设X*是字母表X上的自由幺半群,本文通过以X*为顶点集构造一个语言图Γ(X*),引入语言图Γ(X*)的横截集的概念,给出了极大前缀码的一个刻划.同时,证明了满足含有X中字母且长度有限的极大前缀码必是极大码.  相似文献   

20.
周学光 《数学学报》1958,8(2):200-209
<正> 在[1]中,作者研究了一个(N—1)维连通空间的同伦群和同调群的密切关系,那里所考虑的同伦群的维数是在(2N—2)以内,本文可以看成[1]的继续,我偿将考虑维数在(2N—1)以上而又在(3N—3)以下的同伦群,Betti 数;和上乘积的密切关系.我们  相似文献   

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