{"title":"有限生成模块的结构与未混合度","authors":"Nguyen Tu Cuong , Pham Hung Quy","doi":"10.1016/j.jpaa.2025.108000","DOIUrl":null,"url":null,"abstract":"<div><div>Let <span><math><mo>(</mo><mi>R</mi><mo>,</mo><mi>m</mi><mo>)</mo></math></span> be the homomorphic image of a Cohen-Macaulay local ring and <em>M</em> a finitely generated <em>R</em>-module. We use the splitting of local cohomology to shed a new light on the structure of non-Cohen-Macaulay modules. Namely, we show that every finitely generated <em>R</em>-module <em>M</em> is associated to a sequence of invariant modules. This module sequence expresses the deviation of <em>M</em> with the Cohen-Macaulay property. Our result generalizes the unmixed theorem of Cohen-Macaulayness for any finitely generated <em>R</em>-module. As an application we construct a new extended degree in the sense of Vasconcelos.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 7","pages":"Article 108000"},"PeriodicalIF":0.7000,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On the structure of finitely generated modules and the unmixed degrees\",\"authors\":\"Nguyen Tu Cuong , Pham Hung Quy\",\"doi\":\"10.1016/j.jpaa.2025.108000\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Let <span><math><mo>(</mo><mi>R</mi><mo>,</mo><mi>m</mi><mo>)</mo></math></span> be the homomorphic image of a Cohen-Macaulay local ring and <em>M</em> a finitely generated <em>R</em>-module. We use the splitting of local cohomology to shed a new light on the structure of non-Cohen-Macaulay modules. Namely, we show that every finitely generated <em>R</em>-module <em>M</em> is associated to a sequence of invariant modules. This module sequence expresses the deviation of <em>M</em> with the Cohen-Macaulay property. Our result generalizes the unmixed theorem of Cohen-Macaulayness for any finitely generated <em>R</em>-module. As an application we construct a new extended degree in the sense of Vasconcelos.</div></div>\",\"PeriodicalId\":54770,\"journal\":{\"name\":\"Journal of Pure and Applied Algebra\",\"volume\":\"229 7\",\"pages\":\"Article 108000\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-05-16\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Pure and Applied Algebra\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022404925001392\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Pure and Applied Algebra","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022404925001392","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
On the structure of finitely generated modules and the unmixed degrees
Let be the homomorphic image of a Cohen-Macaulay local ring and M a finitely generated R-module. We use the splitting of local cohomology to shed a new light on the structure of non-Cohen-Macaulay modules. Namely, we show that every finitely generated R-module M is associated to a sequence of invariant modules. This module sequence expresses the deviation of M with the Cohen-Macaulay property. Our result generalizes the unmixed theorem of Cohen-Macaulayness for any finitely generated R-module. As an application we construct a new extended degree in the sense of Vasconcelos.
期刊介绍:
The Journal of Pure and Applied Algebra concentrates on that part of algebra likely to be of general mathematical interest: algebraic results with immediate applications, and the development of algebraic theories of sufficiently general relevance to allow for future applications.