Arithmetic pseudo-Frobenius numbers and determinantal numerical semigroup rings
Abstract
Let H=⟨ a1,…,an⟩ be a numerical semigroup. A conjecture on numerical semigroup rings predicts that the defining ideal IH has a determinantal presentation if and only if the set of pseudo-Frobenius numbers of H has form {h+α,h+2α,…,h+(n−1)α} for h≥ 0, α>0. We prove this conjecture under the condition that h has a unique factorization in H. We also give characterization this unique-factorization condition. As an application, we consider the family of affine-orbit numerical semigroups determined by m=cAn−1+1, 1≤ c≤ a. We prove that the relevant element h has a unique factorization and the defining ideal is generated by the 2-minors of a 2× n-matrix. In particular, the Eagon--Northcott complex of the matrix mentioned above gives the graded minimal free resolution of k[H].
Related
- A criterion for determinantal presentations of numerical semigroup rings
- The Betti numbers and Golodness of numerical semigroup rings of Sally type
- Reflexive ideals of a numerical semigroup
- Betti Sequences of Four-Generated Non-Almost-Symmetric Nearly Gorenstein Numerical Semigroup Rings
- Frobenius Numbers Associated with Primitive Pythagorean Quadruples
BibTeX
@misc{kien2026arithmetic,
title = {{Arithmetic pseudo-Frobenius numbers and determinantal numerical semigroup rings}},
author = {Do Van Kien},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.39218},
eprint = {2609.39218},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.39218},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Arithmetic pseudo-Frobenius numbers and determinantal numerical semigroup rings
AU - Do Van Kien
PY - 2026
DA - 2026/09/30
PB - arXiv
DO - 10.48550/arxiv.2609.39218
UR - https://arxiv.org/abs/2609.39218
AB - Let H=⟨ a_1,…,a_n⟩ be a numerical semigroup. A conjecture on numerical semigroup rings predicts that the defining ideal I_H has a determinantal presentation if and only if the set of pseudo-Frobenius numbers of H has form {h+α,h+2α,…,h+(n−1)α} for h≥ 0, α>0. We prove this conjecture under the condition that h has a unique factorization in H. We also give characterization this unique-factorization condition. As an application, we consider the family of affine-orbit numerical semigroups determined by m=cA_n−1+1, 1≤ c≤ a. We prove that the relevant element h has a unique factorization and the defining ideal is generated by the 2-minors of a 2× n-matrix. In particular, the Eagon--Northcott complex of the matrix mentioned above gives the graded minimal free resolution of k[H].
ER -