Ideal Class Monoid of a Numerical Semigroup

In this repository we present the tools needed to develop the examples in the papers

• L. Casabella, M. D’Anna, P. A. García-Sánchez, Apéry sets and the ideal class monoid of a numerical semigroup, Mediterr. J. Math. 21:7 (2024); arxiv.org/2302.09647,
• P. A. García-Sánchez, The isomorphism problem for ideal class monoids of numerical semigroups, Semigroup Forum (2024), arXiv:2311.15265.
• S. Bonzio, P. A. García-Sánchez, The poset of normalized ideals of numerical semigroups with multiplicity three, arXiv:2407.21697.
• S. Bonzio, P. A. García-Sánchez, When the poset of the ideal class monoid of a numerical semigroup is a lattice, arXiv:2412.07281.

The notebook ideal-class-monoid contains the necessary code (written using the GAP package numericalsgps), together with some examples extracted from the first manuscript. The notebook isomorphism-ideal-class-monoid contains examples for the second manuscript. The file poset-normalized-ideal contains examples and the code needed for the poset of normalized ideals of a numerical semigroup with multiplicity three, while the file lattice-normaliced-ideals-ns has computations dealing with when this poset is a lattice.