English

Almost symmetric numerical semigroups

Commutative Algebra 2018-07-03 v1

Abstract

We study almost symmetric numerical semigroups and semigroup rings. We describe a characteristic property of the minimal free resolution of the semigroup ring of an almost symmetric numerical semigroup. For almost symmetric semigroups generated by 44 elements we will give a structure theorem by using the \lq\lq row-factorization matrices", introduced by Moscariello. As a result, we give a simpler proof of Komeda's structure theorem of pseudo-symmetric numerical semigroups generated by 44 elements. Row-factorization matrices are also used to study shifted families of numerical semigroups.

Keywords

Cite

@article{arxiv.1807.00134,
  title  = {Almost symmetric numerical semigroups},
  author = {Jürgen Herzog and Kei-ichi Watanabe},
  journal= {arXiv preprint arXiv:1807.00134},
  year   = {2018}
}
R2 v1 2026-06-23T02:46:47.311Z