{"title":"分散空间及其紧化","authors":"R.C. Solomon","doi":"10.1016/0016-660X(78)90010-7","DOIUrl":null,"url":null,"abstract":"<div><p>We show that a known restriction on the cardinalities of closures of subspaces of scattered We then find a wide class of spaces, <span><math><mtext>∥</mtext><mtext>A</mtext><mtext>̄</mtext><mtext>∥ ⩽ 2</mtext><msup><mi></mi><mn>∥A∥</mn></msup></math></span>, cannot be improved to <span><math><mtext>∥</mtext><mtext>A</mtext><mtext>̄</mtext><mtext>∥ ⩽ ∥A∥ </mtext><msup><mi></mi><mn>λ</mn></msup></math></span>, for any λ.T.3<span><math><mtext>1</mtext><mtext>2</mtext></math></span>. scattered spaces which have no scattered compactification: these spaces are derived from regular filters over cardinals bigger than <strong>N</strong><sub>1</sub>.</p></div>","PeriodicalId":100574,"journal":{"name":"General Topology and its Applications","volume":"8 3","pages":"Pages 299-301"},"PeriodicalIF":0.0000,"publicationDate":"1978-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0016-660X(78)90010-7","citationCount":"0","resultStr":"{\"title\":\"Scattered spaces and their compactifications\",\"authors\":\"R.C. Solomon\",\"doi\":\"10.1016/0016-660X(78)90010-7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>We show that a known restriction on the cardinalities of closures of subspaces of scattered We then find a wide class of spaces, <span><math><mtext>∥</mtext><mtext>A</mtext><mtext>̄</mtext><mtext>∥ ⩽ 2</mtext><msup><mi></mi><mn>∥A∥</mn></msup></math></span>, cannot be improved to <span><math><mtext>∥</mtext><mtext>A</mtext><mtext>̄</mtext><mtext>∥ ⩽ ∥A∥ </mtext><msup><mi></mi><mn>λ</mn></msup></math></span>, for any λ.T.3<span><math><mtext>1</mtext><mtext>2</mtext></math></span>. scattered spaces which have no scattered compactification: these spaces are derived from regular filters over cardinals bigger than <strong>N</strong><sub>1</sub>.</p></div>\",\"PeriodicalId\":100574,\"journal\":{\"name\":\"General Topology and its Applications\",\"volume\":\"8 3\",\"pages\":\"Pages 299-301\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1978-04-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/0016-660X(78)90010-7\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"General Topology and its Applications\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/0016660X78900107\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"General Topology and its Applications","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0016660X78900107","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
我们证明了对离散子空间闭包的一个已知限制,然后我们发现对于任意λ. t .312,一个广的空间类,∥Ā∥∥a∥,不能改进为∥Ā∥∥a∥λ。没有分散紧化的分散空间:这些空间是由大于N1的基数上的正则过滤器导出的。
We show that a known restriction on the cardinalities of closures of subspaces of scattered We then find a wide class of spaces, , cannot be improved to , for any λ.T.3. scattered spaces which have no scattered compactification: these spaces are derived from regular filters over cardinals bigger than N1.