Nimber-preserving reduction: Game secrets and homomorphic Sprague-Grundy theorem.
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| Title: | Nimber-preserving reduction: Game secrets and homomorphic Sprague-Grundy theorem. |
|---|---|
| Authors: | Burke, Kyle1 (AUTHOR) kburke@flsouthern.edu, Ferland, Matthew1,2 (AUTHOR) mferland@usc.edu, Teng, Shang-hua1,2 (AUTHOR) shanghua@usc.edu |
| Source: | Theoretical Computer Science. Jul2024, Vol. 1005, pN.PAG-N.PAG. 1p. |
| Subjects: | Polynomial time algorithms, Homomorphisms, Cryptography, Game theory, Games |
| Abstract: | The concept of nimbers —a.k.a. Grundy-values or nim-values —is fundamental to combinatorial game theory. Beyond the winnability, nimbers provide a complete characterization of strategic interactions among impartial games in disjunctive sums. In this paper, we consider nimber-preserving reductions among impartial games, which enhance the winnability-preserving reductions in traditional computational characterizations of combinatorial games. We prove that Generalized Geography is complete for the natural class, I P , of polynomially-short impartial rulesets, under polynomial-time nimber-preserving reductions. We refer to this notion of completeness as Sprague-Grundy-completeness. In contrast, we also show that not every PSPACE-complete ruleset in I P is Sprague-Grundy-complete for I P. By viewing every impartial game as an encoding of its nimber—a succinct game secret richer than its winnability alone—our technical result establishes the following striking cryptography-inspired homomorphic theorem: Despite the PSPACE-completeness of nimber computation for I P , there exists a polynomial-time algorithm to construct, for any pair of games G 1 , G 2 in I P , a Generalized Geography game G satisfying: nimber (G) = nimber (G 1) ⊕ nimber (G 2). [ABSTRACT FROM AUTHOR] |
| Copyright of Theoretical Computer Science is the property of Elsevier B.V. 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 |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 178022034 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Nimber-preserving reduction: Game secrets and homomorphic Sprague-Grundy theorem. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Burke%2C+Kyle%22">Burke, Kyle</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> kburke@flsouthern.edu</i><br /><searchLink fieldCode="AR" term="%22Ferland%2C+Matthew%22">Ferland, Matthew</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> mferland@usc.edu</i><br /><searchLink fieldCode="AR" term="%22Teng%2C+Shang-hua%22">Teng, Shang-hua</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> shanghua@usc.edu</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Theoretical+Computer+Science%22">Theoretical Computer Science</searchLink>. Jul2024, Vol. 1005, pN.PAG-N.PAG. 1p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Polynomial+time+algorithms%22">Polynomial time algorithms</searchLink><br /><searchLink fieldCode="DE" term="%22Homomorphisms%22">Homomorphisms</searchLink><br /><searchLink fieldCode="DE" term="%22Cryptography%22">Cryptography</searchLink><br /><searchLink fieldCode="DE" term="%22Game+theory%22">Game theory</searchLink><br /><searchLink fieldCode="DE" term="%22Games%22">Games</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The concept of nimbers —a.k.a. Grundy-values or nim-values —is fundamental to combinatorial game theory. Beyond the winnability, nimbers provide a complete characterization of strategic interactions among impartial games in disjunctive sums. In this paper, we consider nimber-preserving reductions among impartial games, which enhance the winnability-preserving reductions in traditional computational characterizations of combinatorial games. We prove that Generalized Geography is complete for the natural class, I P , of polynomially-short impartial rulesets, under polynomial-time nimber-preserving reductions. We refer to this notion of completeness as Sprague-Grundy-completeness. In contrast, we also show that not every PSPACE-complete ruleset in I P is Sprague-Grundy-complete for I P. By viewing every impartial game as an encoding of its nimber—a succinct game secret richer than its winnability alone—our technical result establishes the following striking cryptography-inspired homomorphic theorem: Despite the PSPACE-completeness of nimber computation for I P , there exists a polynomial-time algorithm to construct, for any pair of games G 1 , G 2 in I P , a Generalized Geography game G satisfying: nimber (G) = nimber (G 1) ⊕ nimber (G 2). [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Theoretical Computer Science is the property of Elsevier B.V. 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: 10.1016/j.tcs.2024.114636 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 1 StartPage: N.PAG Subjects: – SubjectFull: Polynomial time algorithms Type: general – SubjectFull: Homomorphisms Type: general – SubjectFull: Cryptography Type: general – SubjectFull: Game theory Type: general – SubjectFull: Games Type: general Titles: – TitleFull: Nimber-preserving reduction: Game secrets and homomorphic Sprague-Grundy theorem. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Burke, Kyle – PersonEntity: Name: NameFull: Ferland, Matthew – PersonEntity: Name: NameFull: Teng, Shang-hua IsPartOfRelationships: – BibEntity: Dates: – D: 24 M: 07 Text: Jul2024 Type: published Y: 2024 Identifiers: – Type: issn-print Value: 03043975 Numbering: – Type: volume Value: 1005 Titles: – TitleFull: Theoretical Computer Science Type: main |
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