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Flat semigroups and
weighted homogeneous surface singularities
Zsolt Baja and Tamás László |
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Algebraic & Geometric Topology 26 (2026) 201–226
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DOI: 10.2140/agt.2026.26.201
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Abstract |
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We consider numerical semigroups associated with normal weighted homogeneous surface singularities with rational homology sphere links. We say that a semigroup is representable if it can be realized in this way. We characterize the representable semigroups by proving that they are exactly those semigroups which can be written as a quotient of a flat semigroup. As an intermediate step, we study the class of flat semigroups and show that they can be represented by a special subclass of isolated complete intersection singularities whose defining equations can be given explicitly. |
Keywords
numerical semigroups, Frobenius problem, weighted
homogeneous surface singularities, Seifert rational
homology spheres, flat semigroups
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Mathematical Subject Classification
Primary: 20M14, 32S05, 32S25, 32S50
Secondary: 14B05
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References |
Publication
Received: 30 October 2023
Revised: 17 December 2024
Accepted: 9 February 2025
Published: 16 January 2026
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Authors |
| Zsolt Baja | |
| Faculty of Mathematics and Computer
Science Babes-Bolyai University Cluj-Napoca Romania |
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| Tamás László | |
| Faculty of Mathematics and Computer
Science Babes-Bolyai University Cluj-Napoca Romania |
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| © 2026 MSP (Mathematical Sciences Publishers). |
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