{"title":"某些类型余集空间的三空间特性","authors":"Jiewen Chen, Xuewei Ling, Bin Zhao","doi":"10.1016/j.topol.2024.109021","DOIUrl":null,"url":null,"abstract":"<div><p>In this paper, some three-space properties of (compactly-fibered, neutrally-fibered) coset spaces are considered. Let <span><math><mi>X</mi><mo>=</mo><mi>G</mi><mo>/</mo><mi>H</mi></math></span> be a coset space and <em>K</em> a closed subgroup of <em>G</em> with <span><math><mi>H</mi><mo>⊂</mo><mi>K</mi></math></span>. It is mainly shown that (1) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is neutrally-fibered, then <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is second-countable ⇔ <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> are second-countable; (2) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is compactly-fibered such that all compact (resp., countably compact) subspaces of <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> are metrizable, then all compact (resp., countably compact) subspaces of <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> are metrizable; (3) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is neutrally-fibered such that <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> is second-countable and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> an <span><math><msub><mrow><mi>ℵ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>-space (resp., cosmic), then <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is an <span><math><msub><mrow><mi>ℵ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>-space (resp., cosmic); (4) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is neutrally-fibered such that <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> is second-countable and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> has a star-countable <em>cs</em>-network, then <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> has a star-countable <em>cs</em>-network; (5) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is compactly-fibered such that <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> is locally compact metrizable and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> stratifiable (resp., <em>k</em>-semi-stratifiable), then <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is stratifiable (resp., <em>k</em>-semi-stratifiable).</p></div>","PeriodicalId":51201,"journal":{"name":"Topology and its Applications","volume":"355 ","pages":"Article 109021"},"PeriodicalIF":0.6000,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Three-space properties of some kinds of coset spaces\",\"authors\":\"Jiewen Chen, Xuewei Ling, Bin Zhao\",\"doi\":\"10.1016/j.topol.2024.109021\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>In this paper, some three-space properties of (compactly-fibered, neutrally-fibered) coset spaces are considered. Let <span><math><mi>X</mi><mo>=</mo><mi>G</mi><mo>/</mo><mi>H</mi></math></span> be a coset space and <em>K</em> a closed subgroup of <em>G</em> with <span><math><mi>H</mi><mo>⊂</mo><mi>K</mi></math></span>. It is mainly shown that (1) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is neutrally-fibered, then <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is second-countable ⇔ <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> are second-countable; (2) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is compactly-fibered such that all compact (resp., countably compact) subspaces of <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> are metrizable, then all compact (resp., countably compact) subspaces of <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> are metrizable; (3) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is neutrally-fibered such that <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> is second-countable and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> an <span><math><msub><mrow><mi>ℵ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>-space (resp., cosmic), then <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is an <span><math><msub><mrow><mi>ℵ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>-space (resp., cosmic); (4) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is neutrally-fibered such that <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> is second-countable and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> has a star-countable <em>cs</em>-network, then <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> has a star-countable <em>cs</em>-network; (5) If <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is compactly-fibered such that <span><math><mi>K</mi><mo>/</mo><mi>H</mi></math></span> is locally compact metrizable and <span><math><mi>G</mi><mo>/</mo><mi>K</mi></math></span> stratifiable (resp., <em>k</em>-semi-stratifiable), then <span><math><mi>G</mi><mo>/</mo><mi>H</mi></math></span> is stratifiable (resp., <em>k</em>-semi-stratifiable).</p></div>\",\"PeriodicalId\":51201,\"journal\":{\"name\":\"Topology and its Applications\",\"volume\":\"355 \",\"pages\":\"Article 109021\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-07-17\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Topology and its Applications\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0166864124002062\",\"RegionNum\":4,\"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":"Topology and its Applications","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0166864124002062","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
Three-space properties of some kinds of coset spaces
In this paper, some three-space properties of (compactly-fibered, neutrally-fibered) coset spaces are considered. Let be a coset space and K a closed subgroup of G with . It is mainly shown that (1) If is neutrally-fibered, then is second-countable ⇔ and are second-countable; (2) If is compactly-fibered such that all compact (resp., countably compact) subspaces of and are metrizable, then all compact (resp., countably compact) subspaces of are metrizable; (3) If is neutrally-fibered such that is second-countable and an -space (resp., cosmic), then is an -space (resp., cosmic); (4) If is neutrally-fibered such that is second-countable and has a star-countable cs-network, then has a star-countable cs-network; (5) If is compactly-fibered such that is locally compact metrizable and stratifiable (resp., k-semi-stratifiable), then is stratifiable (resp., k-semi-stratifiable).
期刊介绍:
Topology and its Applications is primarily concerned with publishing original research papers of moderate length. However, a limited number of carefully selected survey or expository papers are also included. The mathematical focus of the journal is that suggested by the title: Research in Topology. It is felt that it is inadvisable to attempt a definitive description of topology as understood for this journal. Certainly the subject includes the algebraic, general, geometric, and set-theoretic facets of topology as well as areas of interactions between topology and other mathematical disciplines, e.g. topological algebra, topological dynamics, functional analysis, category theory. Since the roles of various aspects of topology continue to change, the non-specific delineation of topics serves to reflect the current state of research in topology.
At regular intervals, the journal publishes a section entitled Open Problems in Topology, edited by J. van Mill and G.M. Reed. This is a status report on the 1100 problems listed in the book of the same name published by North-Holland in 1990, edited by van Mill and Reed.