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Let $S$ be the numerical semigroup generated by three consecutive numbers $a,a+1,a+2$, where $a\in\mathbb{N}$, $a\geq 3$. We describe the elements of $S$ whose factorizations have all the same length, as well as the set of factorizations of…

Combinatorics · Mathematics 2024-04-10 Pedro A. García-Sánchez , Laura González , Francesc Planas-Vilanova

The pseudo-Frobenius numbers of a numerical semigroup are those gaps of the numerical semigroup that are maximal for the partial order induced by the semigroup. We present a procedure to detect if a given set of integers is the set of…

Commutative Algebra · Mathematics 2019-02-20 M. Delgado , P. A. García-Sánchez , A. M. Robles-Pérez

The change-making problem was recently extended to sets of positive integers not containing the element $1$, and from there to numerical semigroups. A greedy numerical semigroup is defined as a numerical semigroup where the greedy…

Combinatorics · Mathematics 2026-02-24 Arnau Messegué-Buisan , Hebert Pérez-Rosés

We investigate numerical semigroups generated by any quadratic sequence with initial term zero and an infinite number of terms. We find an efficient algorithm for calculating the Ap\'ery set, as well as bounds on the elements of the Ap\'ery…

Group Theory · Mathematics 2020-09-07 Mara Hashuga , Megan Herbine , Alathea Jensen

We define the concentration of a numerical semigroup $S$ as $\mathsf{C}(S)=\max \left\{\text{next}_S(s)-s ~|~ s\in S \backslash \{0\}\right\}$ wherein $\text{next}_S(s)=\min\left\{x \in S ~|~ s<x\right\}$. In this paper, we study the class…

Commutative Algebra · Mathematics 2021-04-01 José C. Rosales , M. B. Branco , Márcio A. Traesel

In this paper, we explore a class of numerical semigroups initiated by Kunz and Waldi containing two coprime numbers $p < q$, which we call KW semigroups. We characterize KW numerical semigroups by their principal matrices. We present a…

Commutative Algebra · Mathematics 2024-05-07 Srishti Singh , Hema Srinivasan

We find a relation between the genus of a quotient of a numerical semigroup $S$ and the genus of $S$ itself. We use this identity to compute the genus of a quotient of $S$ when $S$ has embedding dimension $2$. We also exhibit identities…

This article investigates structural connections between unrefinable partitions into distinct parts and numerical semigroups. By analysing the hooksets of Young diagrams associated with numerical sets, new criteria for recognising…

Combinatorics · Mathematics 2026-01-16 Lorenzo Campioni

The use of compositions simplifies some aspects of the theory of numerical semigroups. We illustrate this by giving a new proof for the asymptotic number C((1 + $\sqrt$ 5)/2) g of numerical semigroups of genus g and by describing the…

Combinatorics · Mathematics 2021-05-11 Roland Bacher

We derive the polynomial representations for minimal relations of generating set of numerical semigroups R_n^k=<(n-1)^k,n^k,(n+1)^k>, k=2,3,4, n>2. We find also the polynomial representations for degrees of syzygies in the Hilbert series…

Commutative Algebra · Mathematics 2016-09-01 Leonid G. Fel

We define a reflective numerical semigroup of genus $g$ as a numerical semigroup that has a certain reflective symmetry when viewed within $\mathbb{Z}$ as an array with $g$ columns. Equivalently, a reflective numerical semigroup has one gap…

Number Theory · Mathematics 2022-07-04 Caleb M. Shor

We study a correspondence between numerical sets and integer partitions that leads to a bijection between simultaneous core partitions and the integer points of a certain polytope. We use this correspondence to prove combinatorial results…

Combinatorics · Mathematics 2022-01-25 Hannah Constantin , Benjamin Houston-Edwards , Nathan Kaplan

We introduce the notion of pattern for numerical semigroups, which allows us to generalize the definition of Arf numerical semigroups. In this way infinitely many other classes of numerical semigroups are defined giving a classification of…

Rings and Algebras · Mathematics 2019-12-10 Maria Bras-Amorós , Pedro García-Sánchez

An affine semigroup is a finitely generated subsemigroup of $(\mathbb Z_{\ge 0}^d, +)$, and a numerical semigroup is an affine semigroup with $d = 1$. A growing body of recent work examines shifted families of numerical semigroups, that is,…

Combinatorics · Mathematics 2021-11-03 Christopher O'Neill , Isabel White

This paper examines in a new way some known facts about numerical semigroups especially when the number of minimal generators (that is the embedding dimension) is at most three and at least two minimal generators are coprime. For such…

Number Theory · Mathematics 2023-09-06 Antoine Mhanna

We present a procedure to enumerate the whole set of numerical semigroups with a given Frobenius number F, S(F). The methodology is based on the construction of a partition of S(F) by a congruence relation. We identify exactly one…

Commutative Algebra · Mathematics 2011-05-26 V. Blanco , J. C. Rosales

There has been significant recent interest in studying how the number of numerical semigroups of genus $g$ behaves as a function of $g$. Bras-Amor\'os has shown how to organize the collection of numerical semigroups of genus $g$ into a…

Combinatorics · Mathematics 2026-03-11 Sogol Cyrusian , Nathan Kaplan

A scale-multiplicative semigroup in a totally disconnected, locally compact group $G$ is one for which the restriction of the scale function on $G$ is multiplicative. The maximal scale-multiplicative semigroups in groups acting…

Group Theory · Mathematics 2013-12-05 Udo Baumgartner , Jacqui Ramagge , George A. Willis

In this paper, we prove that the numerical-semigroup-gap counting problem is #NP-complete as a main theorem. A numerical semigroup is an additive semigroup over the set of all nonnegative integers. A gap of a numerical semigroup is defined…

Computational Complexity · Computer Science 2017-01-05 Shunichi Matsubara

We continue our study of exponent semigroups of rational matrices. Our main result is that the matricial dimension of a numerical semigroup is at most its multiplicity (the least generator), greatly improving upon the previous upper bound…

Combinatorics · Mathematics 2024-07-23 Arsh Chhabra , Stephan Ramon Garcia , Christopher O'Neill