For any space X, either \(C_p(X)\) or \(C_pC_p(X)\) is \(\psi \)-separable

IF 0.6 3区 数学 Q3 MATHEMATICS
J. A. Aguilar-Velázquez, V. V. Tkachuk
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引用次数: 0

Abstract

We establish that, for any Tychonoff space X, at least one of the spaces \(C_p(X)\) and \(C_pC_p(X)\) has a dense subspace of countable pseudocharacter. Under MA, we give an example of a space X such that \(C_p(X)\) does not have a dense subspace of countable functional tightness. We also show that there exists a compact zero-dimensional space K such that \(C_p(K,\{0,1\})\) is exponentially separable while K is not a Sokolov space. For compact scattered spaces K of countable dispersion index, we show that \(C_p(K)\) has a dense exponentially separable subspace if and only if K is \(\omega \)-monolithic. Our results provide answers to several published open questions.

对于任意空间X, \(C_p(X)\)或\(C_pC_p(X)\)都是\(\psi \) -可分离的
证明了对于任意Tychonoff空间X,至少有一个空间\(C_p(X)\)和\(C_pC_p(X)\)具有可数伪特征的稠密子空间。在MA下,我们给出了一个空间X的例子,使得\(C_p(X)\)不存在具有可数功能紧度的稠密子空间。我们还证明了存在一个紧致零维空间K,使得\(C_p(K,\{0,1\})\)是指数可分的,而K不是Sokolov空间。对于具有可数色散指数的紧致散射空间K,证明了\(C_p(K)\)有一个密度指数可分的子空间当且仅当K为\(\omega \) -单片。我们的研究结果为几个公开的开放性问题提供了答案。
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来源期刊
CiteScore
1.50
自引率
11.10%
发文量
77
审稿时长
4-8 weeks
期刊介绍: Acta Mathematica Hungarica is devoted to publishing research articles of top quality in all areas of pure and applied mathematics as well as in theoretical computer science. The journal is published yearly in three volumes (two issues per volume, in total 6 issues) in both print and electronic formats. Acta Mathematica Hungarica (formerly Acta Mathematica Academiae Scientiarum Hungaricae) was founded in 1950 by the Hungarian Academy of Sciences.
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