{"title":"A note on the cardinality of definable families of sets in o-minimal structures","authors":"Pablo Andújar Guerrero","doi":"10.1002/malq.202300030","DOIUrl":null,"url":null,"abstract":"<p>We prove that any definable family of subsets of a definable infinite set <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math> in an o-minimal structure has cardinality at most <span></span><math>\n <semantics>\n <mrow>\n <mo>|</mo>\n <mi>A</mi>\n <mo>|</mo>\n </mrow>\n <annotation>$|A|$</annotation>\n </semantics></math>. We derive some consequences in terms of counting definable types and existence of definable topological spaces.</p>","PeriodicalId":49864,"journal":{"name":"Mathematical Logic Quarterly","volume":"70 4","pages":"361-366"},"PeriodicalIF":0.4000,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/malq.202300030","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mathematical Logic Quarterly","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/malq.202300030","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"LOGIC","Score":null,"Total":0}
引用次数: 0
Abstract
We prove that any definable family of subsets of a definable infinite set in an o-minimal structure has cardinality at most . We derive some consequences in terms of counting definable types and existence of definable topological spaces.
期刊介绍:
Mathematical Logic Quarterly publishes original contributions on mathematical logic and foundations of mathematics and related areas, such as general logic, model theory, recursion theory, set theory, proof theory and constructive mathematics, algebraic logic, nonstandard models, and logical aspects of theoretical computer science.