{"title":"Local Cohomology of Modular Invariant Rings","authors":"Kriti Goel, Jack Jeffries, Anurag K. Singh","doi":"10.1007/s00031-024-09851-6","DOIUrl":null,"url":null,"abstract":"<p>For <i>K</i> a field, consider a finite subgroup <i>G</i> of <span>\\({\\text {GL}}_n(K)\\)</span> with its natural action on the polynomial ring <span>\\(R:= K[x_1,\\dots ,x_n]\\)</span>. Let <span>\\(\\mathfrak {n}\\)</span> denote the homogeneous maximal ideal of the ring of invariants <span>\\(R^G\\)</span>. We study how the local cohomology module <span>\\(H^n_{\\mathfrak {n}}(R^G)\\)</span> compares with <span>\\(H^n_{\\mathfrak {n}}(R)^G\\)</span>. Various results on the <i>a</i>-invariant and on the Hilbert series of <span>\\(H^n_\\mathfrak {n}(R^G)\\)</span> are obtained as a consequence.</p>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s00031-024-09851-6","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
For K a field, consider a finite subgroup G of \({\text {GL}}_n(K)\) with its natural action on the polynomial ring \(R:= K[x_1,\dots ,x_n]\). Let \(\mathfrak {n}\) denote the homogeneous maximal ideal of the ring of invariants \(R^G\). We study how the local cohomology module \(H^n_{\mathfrak {n}}(R^G)\) compares with \(H^n_{\mathfrak {n}}(R)^G\). Various results on the a-invariant and on the Hilbert series of \(H^n_\mathfrak {n}(R^G)\) are obtained as a consequence.