Representations of the Symmetric Group are Decomposable in Polynomial Time.
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| Title: | Representations of the Symmetric Group are Decomposable in Polynomial Time. |
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| Authors: | Olver, Sheehan1 (AUTHOR) s.olver@imperial.ac.uk |
| Source: | Foundations of Computational Mathematics. Apr2026, Vol. 26 Issue 2, p1069-1092. 24p. |
| Subjects: | Representation theory, Polynomial time algorithms, Matrix decomposition, Tensor products, Algorithms, Symmetry groups |
| Abstract: | We introduce an algorithm to decompose matrix representations of the symmetric group over the reals into irreducible representations, which as a by-product also computes the multiplicities of the irreducible representations. The algorithm applied to a d-dimensional representation of S n is shown to have a complexity of O (n 2 d 3) operations for determining which irreducible representations are present and their corresponding multiplicities and a further O (n d 4) operations to fully decompose representations with non-trivial multiplicities. These complexity bounds are pessimistic and in a practical implementation using floating point arithmetic and exploiting sparsity we observe better complexity. We demonstrate this algorithm on the problem of computing multiplicities of two tensor products of irreducible representations (the Kronecker coefficients problem) as well as higher order tensor products. For hook and hook-like irreducible representations the algorithm has polynomial complexity as n increases. We also demonstrate an application to constructing a basis of homogeneous polynomials so that applying a permutation of variables induces an irreducible representation. [ABSTRACT FROM AUTHOR] |
| Copyright of Foundations of Computational Mathematics is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 193283918 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Representations of the Symmetric Group are Decomposable in Polynomial Time. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Olver%2C+Sheehan%22">Olver, Sheehan</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> s.olver@imperial.ac.uk</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Foundations+of+Computational+Mathematics%22">Foundations of Computational Mathematics</searchLink>. Apr2026, Vol. 26 Issue 2, p1069-1092. 24p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Representation+theory%22">Representation theory</searchLink><br /><searchLink fieldCode="DE" term="%22Polynomial+time+algorithms%22">Polynomial time algorithms</searchLink><br /><searchLink fieldCode="DE" term="%22Matrix+decomposition%22">Matrix decomposition</searchLink><br /><searchLink fieldCode="DE" term="%22Tensor+products%22">Tensor products</searchLink><br /><searchLink fieldCode="DE" term="%22Algorithms%22">Algorithms</searchLink><br /><searchLink fieldCode="DE" term="%22Symmetry+groups%22">Symmetry groups</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: We introduce an algorithm to decompose matrix representations of the symmetric group over the reals into irreducible representations, which as a by-product also computes the multiplicities of the irreducible representations. The algorithm applied to a d-dimensional representation of S n is shown to have a complexity of O (n 2 d 3) operations for determining which irreducible representations are present and their corresponding multiplicities and a further O (n d 4) operations to fully decompose representations with non-trivial multiplicities. These complexity bounds are pessimistic and in a practical implementation using floating point arithmetic and exploiting sparsity we observe better complexity. We demonstrate this algorithm on the problem of computing multiplicities of two tensor products of irreducible representations (the Kronecker coefficients problem) as well as higher order tensor products. For hook and hook-like irreducible representations the algorithm has polynomial complexity as n increases. We also demonstrate an application to constructing a basis of homogeneous polynomials so that applying a permutation of variables induces an irreducible representation. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Foundations of Computational Mathematics is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s10208-025-09697-8 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 24 StartPage: 1069 Subjects: – SubjectFull: Representation theory Type: general – SubjectFull: Polynomial time algorithms Type: general – SubjectFull: Matrix decomposition Type: general – SubjectFull: Tensor products Type: general – SubjectFull: Algorithms Type: general – SubjectFull: Symmetry groups Type: general Titles: – TitleFull: Representations of the Symmetric Group are Decomposable in Polynomial Time. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Olver, Sheehan IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 04 Text: Apr2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 16153375 Numbering: – Type: volume Value: 26 – Type: issue Value: 2 Titles: – TitleFull: Foundations of Computational Mathematics Type: main |
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