{"title":"On the relation between pseudocharacters and Chenevier's determinants","authors":"Amit Ophir","doi":"10.1112/blms.13162","DOIUrl":null,"url":null,"abstract":"<p>Consider a commutative unital ring <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math> and a unital <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math>-algebra <span></span><math>\n <semantics>\n <mi>R</mi>\n <annotation>$R$</annotation>\n </semantics></math>. Let <span></span><math>\n <semantics>\n <mi>d</mi>\n <annotation>$d$</annotation>\n </semantics></math> be a positive integer. Chenevier proved that when <span></span><math>\n <semantics>\n <mrow>\n <mo>(</mo>\n <mn>2</mn>\n <mi>d</mi>\n <mo>)</mo>\n <mo>!</mo>\n </mrow>\n <annotation>$(2d)!$</annotation>\n </semantics></math> is invertible in <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math>, the map associating to a determinant its trace is a bijection between <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math>-valued <span></span><math>\n <semantics>\n <mi>d</mi>\n <annotation>$d$</annotation>\n </semantics></math>-dimensional determinants of <span></span><math>\n <semantics>\n <mi>R</mi>\n <annotation>$R$</annotation>\n </semantics></math> and <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math>-valued <span></span><math>\n <semantics>\n <mi>d</mi>\n <annotation>$d$</annotation>\n </semantics></math>-dimensional pseudocharacters of <span></span><math>\n <semantics>\n <mi>R</mi>\n <annotation>$R$</annotation>\n </semantics></math>. In this paper, we show that assuming <span></span><math>\n <semantics>\n <mrow>\n <mi>d</mi>\n <mo>!</mo>\n </mrow>\n <annotation>$d!$</annotation>\n </semantics></math> is invertible in <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math> is sufficient. This assumption is already made in the definition of a <span></span><math>\n <semantics>\n <mi>d</mi>\n <annotation>$d$</annotation>\n </semantics></math>-dimensional pseudocharacter. Our proof involves establishing a product formula for pseudocharacters, which might be of independent interest.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"56 12","pages":"3721-3730"},"PeriodicalIF":0.8000,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.13162","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.13162","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
Consider a commutative unital ring and a unital -algebra . Let be a positive integer. Chenevier proved that when is invertible in , the map associating to a determinant its trace is a bijection between -valued -dimensional determinants of and -valued -dimensional pseudocharacters of . In this paper, we show that assuming is invertible in is sufficient. This assumption is already made in the definition of a -dimensional pseudocharacter. Our proof involves establishing a product formula for pseudocharacters, which might be of independent interest.