首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 125 毫秒
1.
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   

2.
Let X be a uniformly convex Banach space X such that its dual X^* has the KK property. Let C be a nonempty bounded closed convex subset of X and G be a directed system. Let ={Tt : t ∈ G} be a family of asymptotically nonexpansive type mappings on C. In this paper, we investigate the asymptotic behavior of {Ttx0 : t∈ G} and give its weak convergence theorem.  相似文献   

3.
Let(X,)be a measurable space,and,=σ-field generated by {x|x∈X},where x={A∈ |x∈A}.(Y,)another measurable space,let ρ(X, Y,)={∈ |§ be measurable}.∈ρ(X,Y,),we define ()(y)=~(-1)(y),y∈y. Defination 1.T is an index set,f:{0,1}~T→{0,1},then,O~T:( (Y)~x)~T→ (Y)~x is called the operation derived from f if for any { }_(t∈T)∈((Y)~x)~Tand any(x,y)∈X×Y,it holds  相似文献   

4.
Let M be a smooth compact manifold and Λ be a compact invariant set.In this article,we prove that,for every robustly transitive set Λ,f|Λ satisfies a C1-genericstable shadowable property (resp.,C1-gene...  相似文献   

5.
曹金文 《数学季刊》2003,18(3):286-290
This paper proves the following results: Let X = lim← { Xσ,π^σρ,∧ },| ∧ | =λ, and every pro-jection πσ : X → Xσ be an open and onto mapping. (A) If X is λ-paracompact and every Xσ is normal and δθ-refinable, then X is normal and δθ-refinable; (B) If X is hereditarily λ-pamcompact and every Xσ is hereditarily normal and hereditarily δθ-refinable, then X is hereditarily normal and hereditarily δθ-refiable.  相似文献   

6.
Let X= {x_t; t∈T} be a supermartingale (resp. martingale) defined on a probability space (Ω,(?), P) with respect to (?), where (?)={(?)_t; t∈T} is nondecreasing family of sub-σ-algebras of (?). It is well known that (see Theorem 2.27 in [1] ) when T=(?)= {0, 1, …,∞}, the supermartingale (resp. martingale) X possesses the (?)-regularity, i.e., for every τ,σ∈(?) such that τ≤σ,  相似文献   

7.
In this paper,we present that if Y is a hereditarily metacompact space and{Xn:n∈ω}is a countable collection of Cech-scattered metacompact spaces,then the followings are∏equivalent:(1)Y×∏n∈ωXn is metacompact,(2)Y×∏n∈ωXn is countable metacompact,(3)Y×n∈ωXn is orthocompact.Thereby,this result generalizes Theorem 5.4 in[Tanaka,Tsukuba.J.Math.,1993,17:565–587].In addition,we obtain that if Y is a hereditarilyσ-metacompact space and{Xn:n∈ω∏}is a countable collection of Cech-scatteredσ-metacompact spaces,then the product Y×n∈ωXn isσ-metacompact.  相似文献   

8.
Let C be a closed convex weakly Cauchy subset of a normed space X. Then we define a new {a,b,c} type nonexpansive and {a,b,c} type contraction mapping T from C into C. These types of mappings will be denoted respectively by {a,b,c}-ntype and {a,b,c}-ctype. We proved the following: 1. If T is {a,b,c}-ntype mapping, then inf{ || T(x)-x|| :x C C} =0, accordingly T has a unique fixed point. Moreover, any sequence {Xn}n∈NN in C with limn→∞||T(xn) - Xn|| = 0 has a subsequence strongly convergent to the unique fixed point of T. 2. If T is {a,b,c}-ctype mapping, then T has a unique fixed point. Moreover, for any x∈C the sequence of iterates {Tn (x)}n∈N has subsequence strongly convergent to the unique fixed point of T. This paper extends and generalizes some of the results given in [2,4, 7] and [13].  相似文献   

9.
Let G be a non-empty closed(resp.bounded closed)boundedly relatively weakly compact subset in a strictly convex Kadec Banach space X.Let K(X)denote the space of all non-empty compact convex subsets of X endowed with the Hausdorff distance.Moreover,let KG(X)denote the closure of the set {A∈K(x):A∩G=0}.We prove that the set of all A∈KG(X)(resp.A∈K(X)),such that the minimization (resp.maximization)problem min(A,G)(resp.max(A,G))is well posed,contains a dense Gδ-subset of KG(X)(resp.K(X)).thus extending the recent results due to Blasi,Myjak and Papini and Li.  相似文献   

10.
Let K be a local field,that is.K is a locally compactnon-discrete complete and totally disconnected field.A non-Archimedean norm is endowed on K:x→|x|is a mapping from K intoR~+,such that(i)|X|=0 iff X=0;(ii)|xy|=|x||y|;(iii)|x+y|≤max{|x|,|y|}.Then|x|is called the absolute value of x.Theset={x∈K:|x|≤1}is the ring of integers in K,and={x∈K:  相似文献   

11.
σ-满正规空间的逆极限   总被引:3,自引:0,他引:3  
熊朝晖 《数学学报》2004,47(4):819-824
本文证明:设X是逆系统(X_απ_β~α,A}的逆极限,|A|=λ,假设每个投射π_α:X→X_α是开且到上的。X是λ-仿紧和λ-可遮的,如果每个X_α是σ-满正规的(可遮的,σ-集体正规的),则X是σ-满正规的(可造的,σ-集体正规的)。作为这一结果的推论,我们还将证明正规σ-满正规性满足如文[1]中的通常形式的逆极限定理及遗传σ-满正规性的类似结果。  相似文献   

12.
设E是一致凸Banach空间,K是E中非空闭凸集且是一个非扩张收缩核,T:K→E是具非空不动点集F(T):={x∈K:Tx=x}的非扩张映像.设{α_n},{β_n},{γ_n},{α′_n},{β′_n},{γ′_n}是[0,1]中实数列满足α_n+β_n+γ_n=α′_n+γ′_n+γ′_n=1,对任意初值x_1∈K,定义{x_n}如下(ⅰ)如果对偶空间E*具有Kadec-Klee性质,那么{x_n}弱收敛于T的某不动点x*∈F(T);(ⅱ)若T满足(A)条件,那么{x_n}强收敛于T的某不动点x*∈F(T).  相似文献   

13.
Brown运动的逗留时与首中时   总被引:1,自引:0,他引:1  
尹传存 《数学学报》1999,42(4):691-698
设为中的标准Brown运动,对0<α,记本文求出了X在首中球面之前逗留在Bα内的时间的Laplace变换,在首中之前逗留在Bαb内的时间的Laplace变换以及在首中之前逗留在Bαb内的时间的Laplace变换.作为推论,求出了X关于球面首中时的Laplace变换,逗留在球内总的时间的Laplace变换及逗留在球壳内的总的时间的LaPlace变换.  相似文献   

14.
设E是具弱序列连续对偶映像自反Banach空间, C是E中闭凸集, T:C→ C是具非空不动点集F(T)的非扩张映像.给定u∈ C,对任意初值x0∈ C,实数列{αn}n∞=0,{βn}∞n=0∈ (0,1),满足如下条件:(i)sum from n=α to ∞α_n=∞, α_n→0;(ii)β_n∈[0,α) for some α∈(0,1);(iii)sun for n=α to ∞|α_(n-1) α_n|<∞,sum from n=α|β_(n-1)-β_n|<∞设{x_n}_(n_1)~∞是由下式定义的迭代序列:{y_n=β_nx_n (1-β_n)Tx_n x_(n 1)=α_nu (1-α_n)y_n Then {x_n}_(n=1)~∞则{x_n}_(n=1)~∞强收敛于T的某不动点.  相似文献   

15.
假设E为一致凸的Banach空间,对偶空间E*有Kadec-Klee性质,K为E的非空闭凸子集{Ti:i=1,2,…,N}:K→K为Browder-Petryshyn意义下的严格伪压缩映像且F=∩Ni=1F(Ti)≠0.{αn}n∞=1满足0相似文献   

16.
涂振坤  瞿娟 《大学数学》2007,23(4):92-95
得到了如下结果:设X是逆系统{Xα,παβ,Λ}的逆极限,|Λ|=λ,假设每个映射πα∶X→Xα是开的且到上的,X是λ-仿紧,每个Xα是正规可数仿紧的,则X是正规可数仿紧的.进一步得到了关于遗传正规且遗传可数仿紧空间的类似结果.  相似文献   

17.
图 P2×Cn的均匀邻强边色数   总被引:2,自引:0,他引:2  
对图G(V,E),一正常边染色f若满足(1)对(V)uv∈E(G),f[u]≠f[v],其中f[u]={f(uv)|uv∈E};(2)对任意i≠j,有||E|-|Ej||≤1,其中Ei={e| e∈E(G)且f(e)=i}.则称f为G(V,E)的一k-均匀邻强边染色,简称k-EASC,并且称Xcas(G)=min{k|存在G(V,E)的一k-EASC为G(V,E)的均匀邻强边色数.本文得到了图P2×Cn的均匀邻强边色数.  相似文献   

18.
非扩张映象不动点的迭代算法   总被引:2,自引:1,他引:1  
姚永红 《数学学报》2007,50(1):139-144
设C是具有一致Gateaux可微范数的实Banach空间X中的一非空闭凸子集,T是C中不动点集F(T)≠0的一自映象.假设当t→0时,{Xt}强收敛到T的一不动点z,其中xt是C中满足对任给u∈C,xt=tu+(1-t)Txt的唯一确定元.设{αn},{βn}和{γn}是[0,1]中满足下列条件的三个实数列:(i)αn+βn+γn=1;(ii) limn-∞αn=0和.对任意的x0∈C,设序列{xn}定义为xn+1=αnu+βnxn+γnTxn,则{xn}强收敛到T的不动点.  相似文献   

19.
设(Xi,Yi)(i=1,2,…,n)是来自总体(X,Y)的样本(独立同分布),其中X∈R1,Y∈Rq.M(x y)是Y=y时X的条件分布,Mnkn(x y)为M(x y)的第kn个最近邻域的经验分布估计量,讨论条件经验过程Sn(t,x,y)=kn12(Mnkn(x y)-M(x y))的渐近性质,得出在适当条件下,对固定的y,Sn(t,x,y)(x,t为参数)弱收敛于某一G aussian过程S(.).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号