关于元素具有 H 封闭闭合的$$/pi$$-基空间

IF 0.6 3区 数学 Q3 MATHEMATICS
D. Giacopello
{"title":"关于元素具有 H 封闭闭合的$$/pi$$-基空间","authors":"D. Giacopello","doi":"10.1007/s10474-024-01450-x","DOIUrl":null,"url":null,"abstract":"<p>We deal with the class of Hausdorff spaces having a <span>\\(\\pi\\)</span>-base whose elements have an H-closed closure. Carlson proved that <span>\\(|X|\\leq 2^{wL(X)\\psi_c(X)t(X)}\\)</span> for every quasiregular space <span>\\(X\\)</span> with a <span>\\(\\pi\\)</span>-base whose elements have an H-closed closure. We provide an example of a space <span>\\(X\\)</span> having a <span>\\(\\pi\\)</span>-base whose elements have an H-closed closure which is not quasiregular (neither Urysohn) such that <span>\\(|X|&gt; 2^{wL(X)\\chi(X)}\\)</span> (then <span>\\(|X|&gt; 2^{wL(X)\\psi_c(X)t(X)}\\)</span>). Always in the class of spaces with a <span>\\(\\pi\\)</span>-base whose elements have an H-closed closure, we establish the bound <span>\\(|X|\\leq2^{wL(X)k(X)}\\)</span> for Urysohn spaces and we give an example of an Urysohn space <span>\\(Z\\)</span> such that <span>\\(k(Z)&lt;\\chi(Z)\\)</span>. Lastly, we present some equivalent conditions to the Martin's Axiom involving spaces with a <span>\\(\\pi\\)</span>-base whose elements have an H-closed closure and, additionally, we prove that if a quasiregular space has a <span>\\(\\pi\\)</span>-base whose elements have an H-closed closure then such a space is Baire.</p>","PeriodicalId":50894,"journal":{"name":"Acta Mathematica Hungarica","volume":null,"pages":null},"PeriodicalIF":0.6000,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On spaces with a $$\\\\pi$$ -base whose elements have an H-closed closure\",\"authors\":\"D. Giacopello\",\"doi\":\"10.1007/s10474-024-01450-x\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We deal with the class of Hausdorff spaces having a <span>\\\\(\\\\pi\\\\)</span>-base whose elements have an H-closed closure. Carlson proved that <span>\\\\(|X|\\\\leq 2^{wL(X)\\\\psi_c(X)t(X)}\\\\)</span> for every quasiregular space <span>\\\\(X\\\\)</span> with a <span>\\\\(\\\\pi\\\\)</span>-base whose elements have an H-closed closure. We provide an example of a space <span>\\\\(X\\\\)</span> having a <span>\\\\(\\\\pi\\\\)</span>-base whose elements have an H-closed closure which is not quasiregular (neither Urysohn) such that <span>\\\\(|X|&gt; 2^{wL(X)\\\\chi(X)}\\\\)</span> (then <span>\\\\(|X|&gt; 2^{wL(X)\\\\psi_c(X)t(X)}\\\\)</span>). Always in the class of spaces with a <span>\\\\(\\\\pi\\\\)</span>-base whose elements have an H-closed closure, we establish the bound <span>\\\\(|X|\\\\leq2^{wL(X)k(X)}\\\\)</span> for Urysohn spaces and we give an example of an Urysohn space <span>\\\\(Z\\\\)</span> such that <span>\\\\(k(Z)&lt;\\\\chi(Z)\\\\)</span>. Lastly, we present some equivalent conditions to the Martin's Axiom involving spaces with a <span>\\\\(\\\\pi\\\\)</span>-base whose elements have an H-closed closure and, additionally, we prove that if a quasiregular space has a <span>\\\\(\\\\pi\\\\)</span>-base whose elements have an H-closed closure then such a space is Baire.</p>\",\"PeriodicalId\":50894,\"journal\":{\"name\":\"Acta Mathematica Hungarica\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-08-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Acta Mathematica Hungarica\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1007/s10474-024-01450-x\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta Mathematica Hungarica","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s10474-024-01450-x","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0

摘要

我们要讨论的是一类具有其元素具有 H 闭合的 \(\pi\)-base 的 Hausdorff 空间。卡尔森(Carlson)证明了对于每一个具有其元素有一个 H 封闭闭合的基的准线性空间 \(X\) 来说,\(|X|leq 2^{wL(X)\psi_c(X)t(X)}\) 是一个具有 H 封闭闭合的基的准线性空间。我们举例说明了一个有一个其元素有一个 H 封闭闭包的空间 \(X\),它不是类线性的(既不是 Urysohn),这样 \(|X|> 2^{wL(X)\chi(X)}\) (然后 \(|X|>2^{wL(X)\psi_c(X)t(X)}/))。总是在元素具有 H 闭合的、具有 \(\pi\)-base 的空间类别中,我们为 Urysohn 空间建立了约束 \(|X|\leq2^{wL(X)k(X)}\),并给出了一个 Urysohn 空间 \(Z\) 的例子,使得 \(k(Z)<\chi(Z)\)。最后,我们提出了马丁公理(Martin's Axiom)的一些等价条件,这些条件涉及到具有其元素具有 H 封闭闭合的 \(\pi\)-base 的空间,此外,我们还证明了如果一个准线性空间具有其元素具有 H 封闭闭合的 \(\pi\)-base ,那么这样的空间就是拜尔空间。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
On spaces with a $$\pi$$ -base whose elements have an H-closed closure

We deal with the class of Hausdorff spaces having a \(\pi\)-base whose elements have an H-closed closure. Carlson proved that \(|X|\leq 2^{wL(X)\psi_c(X)t(X)}\) for every quasiregular space \(X\) with a \(\pi\)-base whose elements have an H-closed closure. We provide an example of a space \(X\) having a \(\pi\)-base whose elements have an H-closed closure which is not quasiregular (neither Urysohn) such that \(|X|> 2^{wL(X)\chi(X)}\) (then \(|X|> 2^{wL(X)\psi_c(X)t(X)}\)). Always in the class of spaces with a \(\pi\)-base whose elements have an H-closed closure, we establish the bound \(|X|\leq2^{wL(X)k(X)}\) for Urysohn spaces and we give an example of an Urysohn space \(Z\) such that \(k(Z)<\chi(Z)\). Lastly, we present some equivalent conditions to the Martin's Axiom involving spaces with a \(\pi\)-base whose elements have an H-closed closure and, additionally, we prove that if a quasiregular space has a \(\pi\)-base whose elements have an H-closed closure then such a space is Baire.

求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
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.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信