Almost fine gradings on algebras and classification of gradings up to isomorphism
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arXiv
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| Format: | Preprint |
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2023
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| _version_ | 1866915353840320512 |
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| author | Elduque, Alberto Kochetov, Mikhail |
| author_facet | Elduque, Alberto Kochetov, Mikhail |
| contents | We consider the problem of classifying gradings by groups on a finite-dimensional algebra $A$ (with any number of multilinear operations) over an algebraically closed field. We introduce a class of gradings, which we call almost fine, such that every $G$-grading on $A$ is obtained from an almost fine grading on $A$ in an essentially unique way, which is not the case with fine gradings. For abelian groups, we give a method of obtaining all almost fine gradings if fine gradings are known. We apply these ideas to the case of semisimple Lie algebras in characteristic $0$: to any abelian group grading with nonzero identity component, we attach a (possibly nonreduced) root system and, in the simple case, construct an adapted grading by this root system. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2308_07230 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Almost fine gradings on algebras and classification of gradings up to isomorphism Elduque, Alberto Kochetov, Mikhail Rings and Algebras Primary 17A01, Secondary 17A36, 17B70, 16W50, 20G07 We consider the problem of classifying gradings by groups on a finite-dimensional algebra $A$ (with any number of multilinear operations) over an algebraically closed field. We introduce a class of gradings, which we call almost fine, such that every $G$-grading on $A$ is obtained from an almost fine grading on $A$ in an essentially unique way, which is not the case with fine gradings. For abelian groups, we give a method of obtaining all almost fine gradings if fine gradings are known. We apply these ideas to the case of semisimple Lie algebras in characteristic $0$: to any abelian group grading with nonzero identity component, we attach a (possibly nonreduced) root system and, in the simple case, construct an adapted grading by this root system. |
| title | Almost fine gradings on algebras and classification of gradings up to isomorphism |
| topic | Rings and Algebras Primary 17A01, Secondary 17A36, 17B70, 16W50, 20G07 |
| url | https://arxiv.org/abs/2308.07230 |