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THREE KINDS OF DENTABILITIES IN BANACH SPACES AND THEIR APPLICATIONS
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作者 张子厚 周晶 《Acta Mathematica Scientia》 SCIE CSCD 2024年第2期445-454,共10页
In this paper,we study some dentabilities in Banach spaces which are closely related to the famous Radon-Nikodym property.We introduce the concepts of the weak^(*)-weak denting point and the weak^(*)-weak^(*)denting p... In this paper,we study some dentabilities in Banach spaces which are closely related to the famous Radon-Nikodym property.We introduce the concepts of the weak^(*)-weak denting point and the weak^(*)-weak^(*)denting point of a set.These are the generalizations of the weak^(*)denting point of a set in a dual Banach space.By use of the weak^(*)-weak denting point,we characterize the very smooth space,the point of weak^(*)-weak continuity,and the extreme point of a unit ball in a dual Banach space.Meanwhile,we also characterize an approximatively weak compact Chebyshev set in dual Banach spaces.Moreover,we define the nearly weak dentability in Banach spaces,which is a generalization of near dentability.We prove the necessary and sufficient conditions of the reflexivity by nearly weak dentability.We also obtain that nearly weak dentability is equivalent to both the approximatively weak compactness of Banach spaces and the w-strong proximinality of every closed convex subset of Banach spaces. 展开更多
关键词 weak^(*)-weak denting point nearly weak dentability very smooth space point of weak^(*)-weak continuity extreme point approximatively weak compactness w-strong proximinality REFLEXIVITY
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COMPACT DIFFERENCES OF COMPOSITION OPERATORS ON HOLOMORPHIC FUNCTION SPACES IN THE UNIT BALL 被引量:6
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作者 江良英 欧阳才衡 《Acta Mathematica Scientia》 SCIE CSCD 2011年第5期1679-1693,共15页
We find a lower bound for the essential norm of the difference of two composition operators acting on H 2(BN ) or As2 (BN ) (s 1). This result plays an important role in proving a necessary and sufficient condit... We find a lower bound for the essential norm of the difference of two composition operators acting on H 2(BN ) or As2 (BN ) (s 1). This result plays an important role in proving a necessary and sufficient condition for the difference of linear fractional composition operators to be compact, which answers a question posed by MacCluer and Weir in 2005. 展开更多
关键词 composition operators Hardy space Bergman spaces compact differences
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Compact Operators on the Bergman Spaces of the Unit Ball and the Polydisk in C^n 被引量:7
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作者 卢玉峰 《Northeastern Mathematical Journal》 CSCD 2000年第3期347-356,共10页
Let Ω be the unit ball or the polydisk of Cnand L2a(Ω) the Bergman space. In this paper we prove that if S is a finite sum of finite products of Toeplitz operators on L2a( Ω), then S is compact if and only if the B... Let Ω be the unit ball or the polydisk of Cnand L2a(Ω) the Bergman space. In this paper we prove that if S is a finite sum of finite products of Toeplitz operators on L2a( Ω), then S is compact if and only if the Berezin transform S(z) of S tends to zero as z→Ω. 展开更多
关键词 Toeplitz operator compact operator Berezin transform Bergman space
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CHARACTERIZATIONS OF COMPACT OPERATORS ON SOME EULER SPACES OF DIFFERENCE SEQUENCES OF ORDER m 被引量:2
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作者 Ivana Djolovi Eberhard Malkowsky 《Acta Mathematica Scientia》 SCIE CSCD 2011年第4期1465-1474,共10页
In the past, several authors studied spaces of m-th order difference sequences, among them, H.Polat and F.Basar ([17]) defined the Euler spaces of m-th order difference sequences e r 0 (△ ( m ) ), e r c (△ (... In the past, several authors studied spaces of m-th order difference sequences, among them, H.Polat and F.Basar ([17]) defined the Euler spaces of m-th order difference sequences e r 0 (△ ( m ) ), e r c (△ ( m ) ) and e r ∞ (△ ( m ) ) and characterized some classes of matrix transformations on them. In our paper, we add a new supplementary aspect to their research by characterizing classes of compact operators on those spaces. For that purpose, the spaces are treated as the matrix domains of a triangle in the classical sequence spaces c 0 , c and ∞ . The main tool for our characterizations is the Hausdorff measure of noncompactness. 展开更多
关键词 difference sequence spaces of order m matrix transformations compact operators Hausdorff measure of noncompactness
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The Sequence-covering Compact Images of Paracompact Locally Compact Spaces 被引量:4
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作者 李进金 李克典 《Northeastern Mathematical Journal》 CSCD 2000年第4期463-468,共6页
This paper gives internal characterizations of some sequence covering compact images and compact covering compact images of paracompact locally compact spaces, which improve some results on compact images of locally... This paper gives internal characterizations of some sequence covering compact images and compact covering compact images of paracompact locally compact spaces, which improve some results on compact images of locally compact metric spaces. 展开更多
关键词 sequence covering mapping compact covering mapping compact mapping quotient mapping paracompact locally compact space cs cover sn cover cs* cover
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Compactness of Composition Operators from the p-Bloch Space to the q-Bloch Space on the Classical Bounded Symmetric Domains 被引量:1
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作者 Jianbing Su Huijuan Li +1 位作者 Xingxing Miao Rui Wang 《Advances in Pure Mathematics》 2014年第12期649-664,共16页
In this paper, we introduce the weighted Bloch spaces on the first type of classical bounded symmetric domains , and prove the equivalence of the norms and . Furthermore, we study the compactness of composition operat... In this paper, we introduce the weighted Bloch spaces on the first type of classical bounded symmetric domains , and prove the equivalence of the norms and . Furthermore, we study the compactness of composition operator from to , and obtain a sufficient and necessary condition for to be compact. 展开更多
关键词 BLOCH space Classical Bounded Symmetric DOMAINS Composition Operators compactNESS BERGMAN Metric
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Classical Fourier Analysis over Homogeneous Spaces of Compact Groups
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作者 Arash Ghaani Farashahi 《Analysis in Theory and Applications》 CSCD 2016年第4期339-354,共16页
This paper introduces a unified operator theory approach to the abstract Fourier analysis over homogeneous spaces of compact groups. Let G be a compact group and H be a closed subgroup of G. Let G/H be the left coset ... This paper introduces a unified operator theory approach to the abstract Fourier analysis over homogeneous spaces of compact groups. Let G be a compact group and H be a closed subgroup of G. Let G/H be the left coset space of H in G and μ be the normalized G-invariant measure on G/H associated to the Weil's formula. Then, we present a generalized abstract framework of Fourier analysis for the Hilbert function space L^2 (G / H, μ). 展开更多
关键词 compact group homogeneous space dual space Fourier transform Plancherel(trace) formula Peter-Weyl Theorem
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ON COMPACT COMPOSITION OPERATORS ON A CLASS OF HOLOMORPHIC FUNCTION SPACES OVER THE UNIT BALL IN C^n
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作者 龙素娟 《Acta Mathematica Scientia》 SCIE CSCD 2011年第4期1367-1376,共10页
In this paper, a general function space X(B n ) over the unit ball in C n with norm · X(Bn) is introduced. It contains all Hardy space, Bergman space, Besov space etc. The author gives a formulation of a comp... In this paper, a general function space X(B n ) over the unit ball in C n with norm · X(Bn) is introduced. It contains all Hardy space, Bergman space, Besov space etc. The author gives a formulation of a compact composition operator on X(B n ), related to works of [8] and [10]. 展开更多
关键词 compactNESS composition operator function spaces
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Boundeness of a Class of Maximal Operators on H^p Spaces on Compact Lie Groups
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作者 江寅生 《Chinese Quarterly Journal of Mathematics》 CSCD 1993年第4期1-9,共9页
In this paper we discuss the weak type(IP,I)boundedness of a class of maximal operators T and themaximal strong,mean boundedness of a family of the operators {T on the atomic IP spaces on compaet Lie groups.Also,we ob... In this paper we discuss the weak type(IP,I)boundedness of a class of maximal operators T and themaximal strong,mean boundedness of a family of the operators {T on the atomic IP spaces on compaet Lie groups.Also,we obtain the correspoding convergent rosults. 展开更多
关键词 compact Lie group IP spaces boundedness of a class of maximal operators
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METRIC ENTROPY OF HOMEOMORPHISM ON NON-COMPACT METRIC SPACE
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作者 周云华 《Acta Mathematica Scientia》 SCIE CSCD 2011年第1期102-108,共7页
Let T : X → X be a uniformly continuous homeomorphism on a non-compact metric space (X, d). Denote by X* = X ∪ {x*} the one point compactification of X and T * : X* → X* the homeomorphism on X* satisfying... Let T : X → X be a uniformly continuous homeomorphism on a non-compact metric space (X, d). Denote by X* = X ∪ {x*} the one point compactification of X and T * : X* → X* the homeomorphism on X* satisfying T *|X = T and T *x* = x*. We show that their topological entropies satisfy hd(T, X) ≥ h(T *, X*) if X is locally compact. We also give a note on Katok’s measure theoretic entropy on a compact metric space. 展开更多
关键词 Topological entropy metric entropy non-compact metric space one point compactification
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PRODUCT TYPE OPERATORS ACTING BETWEEN WEIGHTED BERGMAN SPACES AND BLOCH TYPE SPACES
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作者 Zuoling LIU Hasi WULAN 《Acta Mathematica Scientia》 SCIE CSCD 2024年第4期1327-1336,共10页
For analytic functions u,ψin the unit disk D in the complex plane and an analytic self-mapφof D,we describe in this paper the boundedness and compactness of product type operators T_(u,ψ,φ)f(z)=u(z)f(φ(z))+ψ(z)f... For analytic functions u,ψin the unit disk D in the complex plane and an analytic self-mapφof D,we describe in this paper the boundedness and compactness of product type operators T_(u,ψ,φ)f(z)=u(z)f(φ(z))+ψ(z)f'(φ(z)),z∈D,acting between weighted Bergman spaces induced by a doubling weight and a Bloch type space with a radial weight. 展开更多
关键词 compactNESS BOUNDEDNESS Bloch type space product type operator weighted Bergman space
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THE COMPACT COMPOSITION OPERATOR ON THE μ-BERGMAN SPACE IN THE UNIT BALL 被引量:7
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作者 黎深莲 张学军 徐思 《Acta Mathematica Scientia》 SCIE CSCD 2017年第2期425-438,共14页
Let p 〉 0 and μ be a normal function on [0, 1), u(r) = (1 - r2)1+n^pμ(r) for r ∈ [0, 1). In this article, the bounded or compact weighted composition operator Tφ,ψ from the μ-Bergman space AP(p) to t... Let p 〉 0 and μ be a normal function on [0, 1), u(r) = (1 - r2)1+n^pμ(r) for r ∈ [0, 1). In this article, the bounded or compact weighted composition operator Tφ,ψ from the μ-Bergman space AP(p) to the normal weight Bloch type space β (r)in the unit ball is characterized. The briefly sufficient and necessary condition that the composition operator Cφ is compact from A^p(μ) to βv, is given. At the same time, the authors give the briefly sufficient and necessary condition that Cv is compact on βμ, for a 〉 1. 展开更多
关键词 μ-Bergman space μ-Bloch space composition operator compactNESS
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COLLECTIVELY COMPACT COMPOSITION OPERATOR SEQUENCES BETWEEN BERGMAN AND HARDY SPACES 被引量:3
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作者 王茂发 刘培德 《Acta Mathematica Scientia》 SCIE CSCD 2004年第2期206-212,共7页
This paper studies the collective compactness of composition operator sequences between the Bergman and Hardy spaces. Some sufficient and necessary conditions involving the generalized Nevanlinna counting functions fo... This paper studies the collective compactness of composition operator sequences between the Bergman and Hardy spaces. Some sufficient and necessary conditions involving the generalized Nevanlinna counting functions for composition operator sequences to be collectively compact between weighted Bergman spaces are given 展开更多
关键词 Bergman space Hardy space composition operator collectively compact operator sequence
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FIXED POINT THEOREMS FOR MAPPINGS SATISFYING IMPLICIT RELATION ON TWO COMPLETE AND COMPACT METRIC SPACES 被引量:3
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作者 Abdlkrim Aliouche Brian Fisher 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第9期1217-1222,共6页
First, the implicit relations were given. A common fixed point theorem was proved for two mappings satisfying implicit relation functions. A further fixed point theorem was proved for mappings satisfying implicit rela... First, the implicit relations were given. A common fixed point theorem was proved for two mappings satisfying implicit relation functions. A further fixed point theorem was proved for mappings satisfying implicit relation functions on two compact metric spaces. 展开更多
关键词 complete metric space compact metric space fixed Points implicit relation
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FIXED POINTS ON TWO COMPLETE AND COMPACT METRIC SPACES 被引量:2
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作者 M. Telci (Department of Mathematics, Faculty of Arts and Science, Trakya University, 22030 Ediren, Turkey) (Communicated by CHIEN Wei_zang) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第5期564-568,共5页
By using functions, some related fixed point theorems on two metric spaces are established. These results generalize some theorems of Fisher.
关键词 fixed point complete metric space compact metric space
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A Short Note on Compactness in Aligned Spaces and Higgs Spaces 被引量:1
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作者 J. M. S. Sim6es-Pereira 《Journal of Mathematics and System Science》 2017年第6期151-153,共3页
We generalize to aligned spaces and to Higgs spaces the concept of compact topological spaces.
关键词 aligned spaces Higgs spaces compactness.
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Almost Fuzzy Compactness in L-fuzzy Topological Spaces
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作者 Li Hong-yan Cui Wei Lei Feng-chun 《Communications in Mathematical Research》 CSCD 2015年第3期267-273,共7页
In this paper, the notion of almost fuzzy compactness is dened in L-fuzzy topological spaces by means of inequality, where L is a completely distributiveDeMorgan algebra. Its properties are discussed and many characte... In this paper, the notion of almost fuzzy compactness is dened in L-fuzzy topological spaces by means of inequality, where L is a completely distributiveDeMorgan algebra. Its properties are discussed and many characterizations of it arepresented. 展开更多
关键词 L-fuzzy topological space L-fuzzy almost compactness L-fuzzy compactness almost fuzzy compactness
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When is an Almost Locally Compact Space Supercomplete?
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作者 李晓婷 林福财 《Chinese Quarterly Journal of Mathematics》 2016年第4期430-434,共5页
It is proved in this paper that(1) the topological sum of a family of supercomplete spaces is supercomplete;(2) if X is a metacompact and almost locally compact space then X is supercomplete. Moreover, some questions ... It is proved in this paper that(1) the topological sum of a family of supercomplete spaces is supercomplete;(2) if X is a metacompact and almost locally compact space then X is supercomplete. Moreover, some questions on supercomplete spaces are posed in the paper. 展开更多
关键词 supercomplete spaces sums of topological spaces almost locally compact metacompact spaces
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MULTIPLIERS ON WEIGHTED FUNCTION SPACES OVER LOCALLY COMPACT VILENKIN GROUPS
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作者 Zhu Yueping (Nantong Teachers College, China) 《Approximation Theory and Its Applications》 2002年第2期65-71,共7页
In this note, we consider the multipliers on weighted function spaces over totally disconnected locally compact abelian groups (Vilenkin groups). Firstly we show an (H1 ,L ) multiplier result. We also give an (Hap ,Ha... In this note, we consider the multipliers on weighted function spaces over totally disconnected locally compact abelian groups (Vilenkin groups). Firstly we show an (H1 ,L ) multiplier result. We also give an (Hap ,Hap) multiplier result under a similiar condition of Lu Yang type. In section 2, we obtain a result about the boundedness of multipliers on weighted Besov spaces. 展开更多
关键词 MATH MULTIPLIERS ON WEIGHTED FUNCTION spaceS OVER LOCALLY compact VILENKIN GROUPS
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RELATIVELY WEAKLY COMPACT SETS IN THE DENJOY SPACE
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作者 Bongiorno Benedetto(Department of Mathematics, Via Archirafiy490123 Palermo ITALY) 《数学研究》 CSCD 1994年第1期37-44,共8页
RELATIVELYWEAKLYCOMPACTSETSINTHEDENJOYSPACE¥BongiornoBenedetto(DepartmentofMathematics,ViaArchirafiy490123Pa... RELATIVELYWEAKLYCOMPACTSETSINTHEDENJOYSPACE¥BongiornoBenedetto(DepartmentofMathematics,ViaArchirafiy490123PalermoITALY)Abstra... 展开更多
关键词 Denjoy空间 相关弱紧集 渐进等连续序列 亨斯托克积分函数
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