{"title":"Ind-étale versus formally étale","authors":"Shubhodip Mondal, Alapan Mukhopadhyay","doi":"10.1112/blms.70025","DOIUrl":null,"url":null,"abstract":"<p>We show that when <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math> is a reduced algebra over a characteristic zero field <span></span><math>\n <semantics>\n <mi>k</mi>\n <annotation>$k$</annotation>\n </semantics></math> and the module of Kähler differentials <span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>Ω</mi>\n <mrow>\n <mi>A</mi>\n <mo>/</mo>\n <mi>k</mi>\n </mrow>\n </msub>\n <mo>=</mo>\n <mn>0</mn>\n </mrow>\n <annotation>$\\Omega _{A/k}=0$</annotation>\n </semantics></math>, then <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math> is ind-étale, partially answering a question of Bhatt. As further applications of this result, we deduce a rigidity property of Hochschild homology and special instances of Weibel's conjecture and Vorst's conjecture without any noetherian assumptions.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 4","pages":"1195-1207"},"PeriodicalIF":0.8000,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of the London Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1112/blms.70025","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
We show that when is a reduced algebra over a characteristic zero field and the module of Kähler differentials , then is ind-étale, partially answering a question of Bhatt. As further applications of this result, we deduce a rigidity property of Hochschild homology and special instances of Weibel's conjecture and Vorst's conjecture without any noetherian assumptions.