{"title":"μ-clubs of Pκ(λ):天堂中的天堂","authors":"Pierre Matet","doi":"10.1016/j.apal.2024.103497","DOIUrl":null,"url":null,"abstract":"<div><p>Let <span><math><mi>μ</mi><mo><</mo><mi>κ</mi><mo><</mo><mi>λ</mi></math></span> be three infinite cardinals, the first two being regular. We show that if there is no inner model with large cardinals, <span><math><mi>u</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>λ</mi><mo>)</mo></math></span> is regular, where <span><math><mi>u</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>λ</mi><mo>)</mo></math></span> denotes the least size of a cofinal subset in <span><math><mo>(</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo><mo>,</mo><mo>⊆</mo><mo>)</mo></math></span>, and <span><math><mrow><mi>cf</mi></mrow><mo>(</mo><mi>λ</mi><mo>)</mo><mo>≠</mo><mi>μ</mi></math></span>, then (a) the <em>μ</em>-club filters on <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> and <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>u</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>λ</mi><mo>)</mo><mo>)</mo></math></span> are isomorphic, and (b) the ideal dual to the <em>μ</em>-club filter on <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> (and hence the restriction of the nonstationary ideal on <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> to sets of uniform cofinality <em>μ</em>) is not <span><math><msub><mrow><mi>I</mi></mrow><mrow><mi>κ</mi><mo>,</mo><mi>λ</mi></mrow></msub></math></span>-<span><math><msub><mrow><mi>b</mi></mrow><mrow><mi>u</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>λ</mi><mo>)</mo></mrow></msub></math></span>-saturated.</p></div>","PeriodicalId":50762,"journal":{"name":"Annals of Pure and Applied Logic","volume":"176 1","pages":"Article 103497"},"PeriodicalIF":0.6000,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"μ-clubs of Pκ(λ): Paradise in heaven\",\"authors\":\"Pierre Matet\",\"doi\":\"10.1016/j.apal.2024.103497\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Let <span><math><mi>μ</mi><mo><</mo><mi>κ</mi><mo><</mo><mi>λ</mi></math></span> be three infinite cardinals, the first two being regular. We show that if there is no inner model with large cardinals, <span><math><mi>u</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>λ</mi><mo>)</mo></math></span> is regular, where <span><math><mi>u</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>λ</mi><mo>)</mo></math></span> denotes the least size of a cofinal subset in <span><math><mo>(</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo><mo>,</mo><mo>⊆</mo><mo>)</mo></math></span>, and <span><math><mrow><mi>cf</mi></mrow><mo>(</mo><mi>λ</mi><mo>)</mo><mo>≠</mo><mi>μ</mi></math></span>, then (a) the <em>μ</em>-club filters on <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> and <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>u</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>λ</mi><mo>)</mo><mo>)</mo></math></span> are isomorphic, and (b) the ideal dual to the <em>μ</em>-club filter on <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> (and hence the restriction of the nonstationary ideal on <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>κ</mi></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> to sets of uniform cofinality <em>μ</em>) is not <span><math><msub><mrow><mi>I</mi></mrow><mrow><mi>κ</mi><mo>,</mo><mi>λ</mi></mrow></msub></math></span>-<span><math><msub><mrow><mi>b</mi></mrow><mrow><mi>u</mi><mo>(</mo><mi>κ</mi><mo>,</mo><mi>λ</mi><mo>)</mo></mrow></msub></math></span>-saturated.</p></div>\",\"PeriodicalId\":50762,\"journal\":{\"name\":\"Annals of Pure and Applied Logic\",\"volume\":\"176 1\",\"pages\":\"Article 103497\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-07-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Annals of Pure and Applied Logic\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0168007224001015\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"LOGIC\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Annals of Pure and Applied Logic","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0168007224001015","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"LOGIC","Score":null,"Total":0}
Let be three infinite cardinals, the first two being regular. We show that if there is no inner model with large cardinals, is regular, where denotes the least size of a cofinal subset in , and , then (a) the μ-club filters on and are isomorphic, and (b) the ideal dual to the μ-club filter on (and hence the restriction of the nonstationary ideal on to sets of uniform cofinality μ) is not --saturated.
期刊介绍:
The journal Annals of Pure and Applied Logic publishes high quality papers in all areas of mathematical logic as well as applications of logic in mathematics, in theoretical computer science and in other related disciplines. All submissions to the journal should be mathematically correct, well written (preferably in English)and contain relevant new results that are of significant interest to a substantial number of logicians. The journal also considers submissions that are somewhat too long to be published by other journals while being too short to form a separate memoir provided that they are of particular outstanding quality and broad interest. In addition, Annals of Pure and Applied Logic occasionally publishes special issues of selected papers from well-chosen conferences in pure and applied logic.