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{"title":"马丁极大值下的完全正规非实紧空间","authors":"Tetsuya Ishiu","doi":"10.1002/malq.202400002","DOIUrl":null,"url":null,"abstract":"<p>We analyze the behavior of a perfectly normal nonrealcompact space <span></span><math>\n <semantics>\n <mrow>\n <mo>(</mo>\n <msub>\n <mi>ω</mi>\n <mn>1</mn>\n </msub>\n <mo>,</mo>\n <mi>τ</mi>\n <mo>)</mo>\n </mrow>\n <annotation>$(\\omega _1, \\tau)$</annotation>\n </semantics></math> on <span></span><math>\n <semantics>\n <msub>\n <mi>ω</mi>\n <mn>1</mn>\n </msub>\n <annotation>$\\omega _1$</annotation>\n </semantics></math> such that for every <span></span><math>\n <semantics>\n <mrow>\n <mi>γ</mi>\n <mo><</mo>\n <msub>\n <mi>ω</mi>\n <mn>1</mn>\n </msub>\n </mrow>\n <annotation>$\\gamma <\\omega _1$</annotation>\n </semantics></math>, <span></span><math>\n <semantics>\n <mi>γ</mi>\n <annotation>$\\gamma$</annotation>\n </semantics></math> is <span></span><math>\n <semantics>\n <mi>τ</mi>\n <annotation>$\\tau$</annotation>\n </semantics></math>-open and <span></span><math>\n <semantics>\n <mrow>\n <mi>γ</mi>\n <mo>+</mo>\n <mi>ω</mi>\n </mrow>\n <annotation>$\\gamma +\\omega$</annotation>\n </semantics></math> is <span></span><math>\n <semantics>\n <mi>τ</mi>\n <annotation>$\\tau$</annotation>\n </semantics></math>-closed under Martin's Maximum. We show that there exists a club subset <span></span><math>\n <semantics>\n <mi>D</mi>\n <annotation>$D$</annotation>\n </semantics></math> of <span></span><math>\n <semantics>\n <msub>\n <mi>ω</mi>\n <mn>1</mn>\n </msub>\n <annotation>$\\omega _1$</annotation>\n </semantics></math> such that for a stationary subset of <span></span><math>\n <semantics>\n <mrow>\n <mi>δ</mi>\n <mo>∈</mo>\n <mo>acc</mo>\n <mo>(</mo>\n <mi>D</mi>\n <mo>)</mo>\n </mrow>\n <annotation>$\\delta \\in \\operatorname{acc}(D)$</annotation>\n </semantics></math>, for all <span></span><math>\n <semantics>\n <mi>τ</mi>\n <annotation>$\\tau$</annotation>\n </semantics></math>-open neighborhood <span></span><math>\n <semantics>\n <mi>N</mi>\n <annotation>$N$</annotation>\n </semantics></math> of <span></span><math>\n <semantics>\n <mrow>\n <mi>δ</mi>\n <mo>+</mo>\n <mi>n</mi>\n </mrow>\n <annotation>$\\delta +n$</annotation>\n </semantics></math>, there exists <span></span><math>\n <semantics>\n <mrow>\n <mi>η</mi>\n <mo><</mo>\n <mi>δ</mi>\n </mrow>\n <annotation>$\\eta <\\delta$</annotation>\n </semantics></math> such that for all <span></span><math>\n <semantics>\n <mrow>\n <mi>ξ</mi>\n <mo>∈</mo>\n <mi>D</mi>\n <mo>∩</mo>\n <mo>[</mo>\n <mi>η</mi>\n <mo>,</mo>\n <mi>δ</mi>\n <mo>)</mo>\n </mrow>\n <annotation>$\\xi \\in D\\cap [\\eta, \\delta)$</annotation>\n </semantics></math>, <span></span><math>\n <semantics>\n <mrow>\n <mi>N</mi>\n <mo>∩</mo>\n <mi>ξ</mi>\n </mrow>\n <annotation>$N\\cap \\xi$</annotation>\n </semantics></math> is unbounded in <span></span><math>\n <semantics>\n <mi>ξ</mi>\n <annotation>$\\xi$</annotation>\n </semantics></math>.</p>","PeriodicalId":49864,"journal":{"name":"Mathematical Logic Quarterly","volume":"70 4","pages":"388-397"},"PeriodicalIF":0.4000,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/malq.202400002","citationCount":"0","resultStr":"{\"title\":\"Perfectly normal nonrealcompact spaces under Martin's Maximum\",\"authors\":\"Tetsuya Ishiu\",\"doi\":\"10.1002/malq.202400002\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We analyze the behavior of a perfectly normal nonrealcompact space <span></span><math>\\n <semantics>\\n <mrow>\\n <mo>(</mo>\\n <msub>\\n <mi>ω</mi>\\n <mn>1</mn>\\n </msub>\\n <mo>,</mo>\\n <mi>τ</mi>\\n <mo>)</mo>\\n </mrow>\\n <annotation>$(\\\\omega _1, \\\\tau)$</annotation>\\n </semantics></math> on <span></span><math>\\n <semantics>\\n <msub>\\n <mi>ω</mi>\\n <mn>1</mn>\\n </msub>\\n <annotation>$\\\\omega _1$</annotation>\\n </semantics></math> such that for every <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>γ</mi>\\n <mo><</mo>\\n <msub>\\n <mi>ω</mi>\\n <mn>1</mn>\\n </msub>\\n </mrow>\\n <annotation>$\\\\gamma <\\\\omega _1$</annotation>\\n </semantics></math>, <span></span><math>\\n <semantics>\\n <mi>γ</mi>\\n <annotation>$\\\\gamma$</annotation>\\n </semantics></math> is <span></span><math>\\n <semantics>\\n <mi>τ</mi>\\n <annotation>$\\\\tau$</annotation>\\n </semantics></math>-open and <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>γ</mi>\\n <mo>+</mo>\\n <mi>ω</mi>\\n </mrow>\\n <annotation>$\\\\gamma +\\\\omega$</annotation>\\n </semantics></math> is <span></span><math>\\n <semantics>\\n <mi>τ</mi>\\n <annotation>$\\\\tau$</annotation>\\n </semantics></math>-closed under Martin's Maximum. We show that there exists a club subset <span></span><math>\\n <semantics>\\n <mi>D</mi>\\n <annotation>$D$</annotation>\\n </semantics></math> of <span></span><math>\\n <semantics>\\n <msub>\\n <mi>ω</mi>\\n <mn>1</mn>\\n </msub>\\n <annotation>$\\\\omega _1$</annotation>\\n </semantics></math> such that for a stationary subset of <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>δ</mi>\\n <mo>∈</mo>\\n <mo>acc</mo>\\n <mo>(</mo>\\n <mi>D</mi>\\n <mo>)</mo>\\n </mrow>\\n <annotation>$\\\\delta \\\\in \\\\operatorname{acc}(D)$</annotation>\\n </semantics></math>, for all <span></span><math>\\n <semantics>\\n <mi>τ</mi>\\n <annotation>$\\\\tau$</annotation>\\n </semantics></math>-open neighborhood <span></span><math>\\n <semantics>\\n <mi>N</mi>\\n <annotation>$N$</annotation>\\n </semantics></math> of <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>δ</mi>\\n <mo>+</mo>\\n <mi>n</mi>\\n </mrow>\\n <annotation>$\\\\delta +n$</annotation>\\n </semantics></math>, there exists <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>η</mi>\\n <mo><</mo>\\n <mi>δ</mi>\\n </mrow>\\n <annotation>$\\\\eta <\\\\delta$</annotation>\\n </semantics></math> such that for all <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>ξ</mi>\\n <mo>∈</mo>\\n <mi>D</mi>\\n <mo>∩</mo>\\n <mo>[</mo>\\n <mi>η</mi>\\n <mo>,</mo>\\n <mi>δ</mi>\\n <mo>)</mo>\\n </mrow>\\n <annotation>$\\\\xi \\\\in D\\\\cap [\\\\eta, \\\\delta)$</annotation>\\n </semantics></math>, <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>N</mi>\\n <mo>∩</mo>\\n <mi>ξ</mi>\\n </mrow>\\n <annotation>$N\\\\cap \\\\xi$</annotation>\\n </semantics></math> is unbounded in <span></span><math>\\n <semantics>\\n <mi>ξ</mi>\\n <annotation>$\\\\xi$</annotation>\\n </semantics></math>.</p>\",\"PeriodicalId\":49864,\"journal\":{\"name\":\"Mathematical Logic Quarterly\",\"volume\":\"70 4\",\"pages\":\"388-397\"},\"PeriodicalIF\":0.4000,\"publicationDate\":\"2024-10-16\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1002/malq.202400002\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Mathematical Logic Quarterly\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1002/malq.202400002\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"LOGIC\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mathematical Logic Quarterly","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/malq.202400002","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"LOGIC","Score":null,"Total":0}
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