{"title":"Greenberg's conjecture for real quadratic fields and the cyclotomic Z2-extensions","authors":"L. Pagani","doi":"10.1090/mcom/3712","DOIUrl":null,"url":null,"abstract":"Let $\\mathcal{A}_n$ be the $2$-part of the ideal class group of the $n$-th layer of the cyclotomic $\\mathbb{Z}_2$-extension of a real quadratic number field $F$. The cardinality of $\\mathcal{A}_n$ is related to the index of cyclotomic units in the full group of units. We present a method to study the latter index. As an application we show that the sequence of the $\\mathcal{A}_n$'s stabilizes for the real fields $F=\\mathbb{Q}(\\sqrt{f})$ for any integer $0<f<10000$. Equivalently Greenberg's conjecture holds for those fields.","PeriodicalId":18301,"journal":{"name":"Math. Comput. Model.","volume":"39 1","pages":"1437-1467"},"PeriodicalIF":0.0000,"publicationDate":"2021-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"5","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Math. Comput. Model.","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1090/mcom/3712","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 5
Abstract
Let $\mathcal{A}_n$ be the $2$-part of the ideal class group of the $n$-th layer of the cyclotomic $\mathbb{Z}_2$-extension of a real quadratic number field $F$. The cardinality of $\mathcal{A}_n$ is related to the index of cyclotomic units in the full group of units. We present a method to study the latter index. As an application we show that the sequence of the $\mathcal{A}_n$'s stabilizes for the real fields $F=\mathbb{Q}(\sqrt{f})$ for any integer $0
设$\mathcal{A}_n$是实二次元域$F$的环切$\mathbb{Z}_2$扩展的$n$第n$层理想类群的$2$部分。$\mathcal{A}_n$的基数与整组环切单位的索引有关。本文提出了一种研究后一指标的方法。作为一个应用,我们证明了$\mathcal{A}_n$的序列对于实域$F=\mathbb{Q}(\sqrt{F})$对于任意整数$0< F <10000$是稳定的。格林伯格的猜想同样适用于这些领域。