English

Distribution of genus among numerical semigroups with fixed Frobenius number

Combinatorics 2020-08-10 v1

Abstract

A numerical semigroup is a sub-semigroup of the natural numbers that has a finite complement. The size of its complement is called the genus and the largest number in the complement is called its Frobenius number. We consider the set of numerical semigroups with a fixed Frobenius number ff and analyse their genus. We find the asymptotic distribution of genus in this set of numerical semigroups and show that it is a product of a Gaussian and a power series. We show that almost all numerical semigroups with Frobenius number ff have genus close to 3f4\frac{3f}{4}. We denote the number of numerical semigroups of Frobenius number ff by N(f)N(f). While N(f)N(f) is not monotonic we prove that N(f)<N(f+2)N(f)<N(f+2) for every ff.

Keywords

Cite

@article{arxiv.2008.02963,
  title  = {Distribution of genus among numerical semigroups with fixed Frobenius number},
  author = {Deepesh Singhal},
  journal= {arXiv preprint arXiv:2008.02963},
  year   = {2020}
}

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18 pages