Abstract
A numerical semigroup S is closed under addition of its divisors (\({\mathcal {C}}\)-semigroup) if the following condition holds: if \(s\in S\setminus \{0\}\) and d is a non trivial divisor of s then \(s+d\in S\). In this paper we prove that the set of all \({\mathcal {C}}\)-semigroups is a Frobenius variety. As a consequence, we give algorithms to compute the set \({\mathcal {C}}\)-semigroups with fixed multiplicity, genus and Frobenius number.
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We thank the anonymous referees for their detailed suggestions and comments, which have greatly improved this manuscript.
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The fist author was partially supported by the research group FQM-343 FQM-5849 (Junta de Andalucia/Feder) and by the Project MTM2017-84890-P (MINECO/FEDER, UE). The second author is supported by the Project FCT PTDC/MAT/73544/2006). 2010 Mathematics Subject Classification: 20M14, 11D07.
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Rosales, J.C., Branco, M.B. Numerical semigroups closed under addition of their divisors. AAECC 32, 665–680 (2021). https://doi.org/10.1007/s00200-020-00420-4
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DOI: https://doi.org/10.1007/s00200-020-00420-4