{"title":"Notes on endomorphisms, local cohomology and completion","authors":"P. Schenzel","doi":"10.1090/conm/773/15540","DOIUrl":null,"url":null,"abstract":"<p>Let <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper M\">\n <mml:semantics>\n <mml:mi>M</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">M</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> denote a finitely generated module over a Noetherian ring <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper R\">\n <mml:semantics>\n <mml:mi>R</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">R</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>. For an ideal <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper I subset-of upper R\">\n <mml:semantics>\n <mml:mrow>\n <mml:mi>I</mml:mi>\n <mml:mo>⊂<!-- ⊂ --></mml:mo>\n <mml:mi>R</mml:mi>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">I \\subset R</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> there is a study of the endomorphisms of the local cohomology module <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper H Subscript upper I Superscript g Baseline left-parenthesis upper M right-parenthesis comma g equals g r a d e left-parenthesis upper I comma upper M right-parenthesis comma\">\n <mml:semantics>\n <mml:mrow>\n <mml:msubsup>\n <mml:mi>H</mml:mi>\n <mml:mi>I</mml:mi>\n <mml:mi>g</mml:mi>\n </mml:msubsup>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>M</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mo>,</mml:mo>\n <mml:mi>g</mml:mi>\n <mml:mo>=</mml:mo>\n <mml:mi>g</mml:mi>\n <mml:mi>r</mml:mi>\n <mml:mi>a</mml:mi>\n <mml:mi>d</mml:mi>\n <mml:mi>e</mml:mi>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>I</mml:mi>\n <mml:mo>,</mml:mo>\n <mml:mi>M</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mo>,</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">H^g_I(M), g = grade(I,M),</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula> and related results. Another subject is the study of left derived functors of the <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"upper I\">\n <mml:semantics>\n <mml:mi>I</mml:mi>\n <mml:annotation encoding=\"application/x-tex\">I</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>-adic completion <inline-formula content-type=\"math/mathml\">\n<mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" alttext=\"normal upper Lamda Subscript i Superscript upper I Baseline left-parenthesis upper H Subscript upper I Superscript g Baseline left-parenthesis upper M right-parenthesis right-parenthesis\">\n <mml:semantics>\n <mml:mrow>\n <mml:msubsup>\n <mml:mi mathvariant=\"normal\">Λ<!-- Λ --></mml:mi>\n <mml:mi>i</mml:mi>\n <mml:mi>I</mml:mi>\n </mml:msubsup>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:msubsup>\n <mml:mi>H</mml:mi>\n <mml:mi>I</mml:mi>\n <mml:mi>g</mml:mi>\n </mml:msubsup>\n <mml:mo stretchy=\"false\">(</mml:mo>\n <mml:mi>M</mml:mi>\n <mml:mo stretchy=\"false\">)</mml:mo>\n <mml:mo stretchy=\"false\">)</mml:mo>\n </mml:mrow>\n <mml:annotation encoding=\"application/x-tex\">\\Lambda ^I_i(H^g_I(M))</mml:annotation>\n </mml:semantics>\n</mml:math>\n</inline-formula>, motivated by a characterization of Gorenstein rings given in <bold>[25]</bold>. This provides another Cohen-Macaulay criterion. The results are illustrated by several examples. There is also an extension to the case of homomorphisms of two different local cohomology modules.</p>","PeriodicalId":49037,"journal":{"name":"Journal of Commutative Algebra","volume":"18 1","pages":""},"PeriodicalIF":0.3000,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Commutative Algebra","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1090/conm/773/15540","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 3
Abstract
Let MM denote a finitely generated module over a Noetherian ring RR. For an ideal I⊂RI \subset R there is a study of the endomorphisms of the local cohomology module HIg(M),g=grade(I,M),H^g_I(M), g = grade(I,M), and related results. Another subject is the study of left derived functors of the II-adic completion ΛiI(HIg(M))\Lambda ^I_i(H^g_I(M)), motivated by a characterization of Gorenstein rings given in [25]. This provides another Cohen-Macaulay criterion. The results are illustrated by several examples. There is also an extension to the case of homomorphisms of two different local cohomology modules.
设M M表示诺瑟环rr上有限生成的模。对于理想I∧R I \子集R,研究了局部上同模H I g (M), g = g R ade(I,M), H^g_I(M), g = grade(I,M)的自同态及其相关结果。另一个主题是研究I - I进补全Λ I I(H I g (M)) \Lambda ^I_i(H^g_I(M))的左衍生函子,其动机是在[25]中给出的Gorenstein环的表征。这提供了另一个科恩-麦考利标准。通过几个实例说明了结果。对于两个不同的局部上同模的同态也有一个推广。
期刊介绍:
Journal of Commutative Algebra publishes significant results in the area of commutative algebra and closely related fields including algebraic number theory, algebraic geometry, representation theory, semigroups and monoids.
The journal also publishes substantial expository/survey papers as well as conference proceedings. Any person interested in editing such a proceeding should contact one of the managing editors.