{"title":"Ext 和 Tor 上的同调算子环","authors":"Samuel Alvite, Javier Majadas","doi":"arxiv-2408.00730","DOIUrl":null,"url":null,"abstract":"For any homomorphism of commutative rings $A \\to B$ and a $B$-module $M$, we\nconstruct a structure of graded $\\mathrm{S}_B^{\\ast}\\mathrm{H}^1(A,B,B)$-module\non $\\mathrm{Ext}_B^{\\ast}(M,M)$ and $\\mathrm{Tor}_{\\ast}^B(M,M)$, where\n$\\mathrm{H}^1(A,B,B)$ is the first Andr\\'e-Quillen cohomology module and\n$\\mathrm{S}^{\\ast}$ denotes the symmetric algebra. This structure generalizes\nthe well known structures of $B[X_1, \\dots, X_n]$-module constructed by\nGulliksen when $B=R/I$ and $I$ is generated by a regular sequence of length $n$\n(in this case, $\\mathrm{S}_B^{\\ast}\\mathrm{H}^1(R,B,B)= \\mathrm{S}_B^{\\ast}\n\\left(\\widehat{I/I^2}\\right)=B[X_1, \\dots, X_n]$), but the main interest is\nthat for any such $B=R/I$, Gulliksen operations factorize through the ring\n$\\mathrm{S}_B^{\\ast}\\mathrm{H}^1(A,B,B)$ for any ring $A$ such that $R$ is an\n$A$-algebra, allowing us to think that, for some purposes, in order to define\nthese cohomological operations, Andr\\'e-Quillen cohomology is a more natural\nchoice than the normal module $\\widehat{I/I^2}$.","PeriodicalId":501475,"journal":{"name":"arXiv - MATH - Commutative Algebra","volume":"30 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"A ring of cohomological operators on Ext and Tor\",\"authors\":\"Samuel Alvite, Javier Majadas\",\"doi\":\"arxiv-2408.00730\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"For any homomorphism of commutative rings $A \\\\to B$ and a $B$-module $M$, we\\nconstruct a structure of graded $\\\\mathrm{S}_B^{\\\\ast}\\\\mathrm{H}^1(A,B,B)$-module\\non $\\\\mathrm{Ext}_B^{\\\\ast}(M,M)$ and $\\\\mathrm{Tor}_{\\\\ast}^B(M,M)$, where\\n$\\\\mathrm{H}^1(A,B,B)$ is the first Andr\\\\'e-Quillen cohomology module and\\n$\\\\mathrm{S}^{\\\\ast}$ denotes the symmetric algebra. This structure generalizes\\nthe well known structures of $B[X_1, \\\\dots, X_n]$-module constructed by\\nGulliksen when $B=R/I$ and $I$ is generated by a regular sequence of length $n$\\n(in this case, $\\\\mathrm{S}_B^{\\\\ast}\\\\mathrm{H}^1(R,B,B)= \\\\mathrm{S}_B^{\\\\ast}\\n\\\\left(\\\\widehat{I/I^2}\\\\right)=B[X_1, \\\\dots, X_n]$), but the main interest is\\nthat for any such $B=R/I$, Gulliksen operations factorize through the ring\\n$\\\\mathrm{S}_B^{\\\\ast}\\\\mathrm{H}^1(A,B,B)$ for any ring $A$ such that $R$ is an\\n$A$-algebra, allowing us to think that, for some purposes, in order to define\\nthese cohomological operations, Andr\\\\'e-Quillen cohomology is a more natural\\nchoice than the normal module $\\\\widehat{I/I^2}$.\",\"PeriodicalId\":501475,\"journal\":{\"name\":\"arXiv - MATH - Commutative Algebra\",\"volume\":\"30 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-08-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - MATH - Commutative Algebra\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2408.00730\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - MATH - Commutative Algebra","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2408.00730","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
For any homomorphism of commutative rings $A \to B$ and a $B$-module $M$, we
construct a structure of graded $\mathrm{S}_B^{\ast}\mathrm{H}^1(A,B,B)$-module
on $\mathrm{Ext}_B^{\ast}(M,M)$ and $\mathrm{Tor}_{\ast}^B(M,M)$, where
$\mathrm{H}^1(A,B,B)$ is the first Andr\'e-Quillen cohomology module and
$\mathrm{S}^{\ast}$ denotes the symmetric algebra. This structure generalizes
the well known structures of $B[X_1, \dots, X_n]$-module constructed by
Gulliksen when $B=R/I$ and $I$ is generated by a regular sequence of length $n$
(in this case, $\mathrm{S}_B^{\ast}\mathrm{H}^1(R,B,B)= \mathrm{S}_B^{\ast}
\left(\widehat{I/I^2}\right)=B[X_1, \dots, X_n]$), but the main interest is
that for any such $B=R/I$, Gulliksen operations factorize through the ring
$\mathrm{S}_B^{\ast}\mathrm{H}^1(A,B,B)$ for any ring $A$ such that $R$ is an
$A$-algebra, allowing us to think that, for some purposes, in order to define
these cohomological operations, Andr\'e-Quillen cohomology is a more natural
choice than the normal module $\widehat{I/I^2}$.