{"title":"如果Rm = Rn必须m = n?","authors":"Tyrone Crisp","doi":"10.1080/00029890.2023.2184163","DOIUrl":null,"url":null,"abstract":"A fundamental theorem of linear algebra asserts that every basis for the vector space Rn has n elements. In this expository note we present a theorem of W. G. Leavitt describing one way in which this invariant basis number property can fail when one does linear algebra over rings, rather than over fields. We give a proof of Leavitt’s theorem that combines ideas of P. M. Cohn and A. L. S. Corner into an elementary form requiring only a nodding acquaintance with matrices and modular arithmetic.","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"If <i>R<sup>m</sup></i> ≅ <i>R<sup>n</sup></i> must <i>m</i> = <i>n</i>?\",\"authors\":\"Tyrone Crisp\",\"doi\":\"10.1080/00029890.2023.2184163\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"A fundamental theorem of linear algebra asserts that every basis for the vector space Rn has n elements. In this expository note we present a theorem of W. G. Leavitt describing one way in which this invariant basis number property can fail when one does linear algebra over rings, rather than over fields. We give a proof of Leavitt’s theorem that combines ideas of P. M. Cohn and A. L. S. Corner into an elementary form requiring only a nodding acquaintance with matrices and modular arithmetic.\",\"PeriodicalId\":0,\"journal\":{\"name\":\"\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0,\"publicationDate\":\"2023-03-21\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1080/00029890.2023.2184163\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1080/00029890.2023.2184163","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
线性代数的一个基本定理断言向量空间Rn的每一组基有n个元素。在这篇说述性的笔记中,我们提出了W. G. Leavitt的一个定理,该定理描述了当人们在环上而不是在域上做线性代数时,这个不变基数性质可能失效的一种方式。我们给出了莱维特定理的一个证明,这个证明结合了P. M. Cohn和a . L. S. Corner的思想,形成了一个初等的形式,只需要对矩阵和模运算略知一知。
A fundamental theorem of linear algebra asserts that every basis for the vector space Rn has n elements. In this expository note we present a theorem of W. G. Leavitt describing one way in which this invariant basis number property can fail when one does linear algebra over rings, rather than over fields. We give a proof of Leavitt’s theorem that combines ideas of P. M. Cohn and A. L. S. Corner into an elementary form requiring only a nodding acquaintance with matrices and modular arithmetic.