scholarly journals Numerical semigroups bounded by the translation of a plane monoid

Author(s):  
M. A. Moreno-Frías ◽  
J. C. Rosales

AbstractLet $$\mathbb {N}$$ N be the set of nonnegative integer numbers. A plane monoid is a submonoid of $$(\mathbb {N}^2,+)$$ ( N 2 , + ) . Let M be a plane monoid and $$p,q\in \mathbb {N}$$ p , q ∈ N . We will say that an integer number n is M(p, q)-bounded if there is $$(a,b)\in M$$ ( a , b ) ∈ M such that $$a+p\le n \le b-q$$ a + p ≤ n ≤ b - q . We will denote by $${\mathrm A}(M(p,q))=\{n\in \mathbb {N}\mid n \text { is } M(p,q)\text {-bounded}\}.$$ A ( M ( p , q ) ) = { n ∈ N ∣ n is M ( p , q ) -bounded } . An $$\mathcal {A}(p,q)$$ A ( p , q ) -semigroup is a numerical semigroup S such that $$S= {\mathrm A}(M(p,q))\cup \{0\}$$ S = A ( M ( p , q ) ) ∪ { 0 } for some plane monoid M. In this work we will study these kinds of numerical semigroups.

2017 ◽  
Vol 29 (2) ◽  
pp. 329-345 ◽  
Author(s):  
Aureliano M. Robles-Pérez ◽  
José Carlos Rosales

AbstractLet ${{\mathbb{N}}}$ be the set of nonnegative integers. A problem about how to transport profitably an organized group of persons leads us to study the set T formed by the integers n such that the system of inequalities, with nonnegative integer coefficients,$a_{1}x_{1}+\cdots+a_{p}x_{p}<n<b_{1}x_{1}+\cdots+b_{p}x_{p}$has at least one solution in ${{\mathbb{N}}^{p}}$. We will see that ${T\cup\{0\}}$ is a numerical semigroup. Moreover, we will show that a numerical semigroup S can be obtained in this way if and only if ${\{a+b-1,a+b+1\}\subseteq S}$, for all ${a,b\in S\setminus\{0\}}$. In addition, we will demonstrate that such numerical semigroups form a Frobenius variety and we will study this variety. Finally, we show an algorithmic process in order to compute T.


2015 ◽  
Vol 25 (06) ◽  
pp. 1043-1053 ◽  
Author(s):  
Francesco Strazzanti

Given two numerical semigroups S and T and a positive integer d, S is said to be one over d of T if S = {s ∈ ℕ | ds ∈ T} and in this case T is called a d-fold of S. We prove that the minimal genus of the d-folds of S is [Formula: see text], where g and f denote the genus and the Frobenius number of S. The case d = 2 is a problem proposed by Robles-Pérez, Rosales, and Vasco. Furthermore, we find the minimal genus of the symmetric doubles of S and study the particular case when S is almost symmetric. Finally, we study the Frobenius number of the quotient of some families of numerical semigroups.


2019 ◽  
Vol 29 (5) ◽  
pp. 345-350
Author(s):  
Ze Gu

Abstract Given a numerical semigroup S, a nonnegative integer a and m ∈ S ∖ {0}, we introduce the set C(S, a, m) = {s + aw(s mod m) | s ∈ S}, where {w(0), w(1), ⋯, w(m – 1)} is the Apéry set of m in S. In this paper we characterize the pairs (a, m) such that C(S, a, m) is a numerical semigroup. We study the principal invariants of C(S, a, m) which are given explicitly in terms of invariants of S. We also characterize the compositions C(S, a, m) that are symmetric, pseudo-symmetric and almost symmetric. Finally, a result about compliance to Wilf’s conjecture of C(S, a, m) is given.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Aureliano M. Robles-Pérez ◽  
José Carlos Rosales

Let𝒜be an alphabet with two elements. Considering a particular class of words (the phrases) over such an alphabet, we connect with the theory of numerical semigroups. We study the properties of the family of numerical semigroups which arise from this starting point.


2017 ◽  
Vol 16 (11) ◽  
pp. 1750209 ◽  
Author(s):  
P. A. García-Sánchez ◽  
B. A. Heredia ◽  
H. İ. Karakaş ◽  
J. C. Rosales

We present procedures to calculate the set of Arf numerical semigroups with given genus, given conductor and given genus and conductor. We characterize the Kunz coordinates of an Arf numerical semigroup. We also describe Arf numerical semigroups with fixed Frobenius number and multiplicity up to 7.


2015 ◽  
Vol 15 (01) ◽  
pp. 1650007 ◽  
Author(s):  
S. T. Chapman ◽  
P. A. García-Sánchez ◽  
Z. Tripp ◽  
C. Viola

In this paper, we find the ω-value of the generators of any numerical semigroup with embedding dimension three. This allows us to determine all possible orderings of the ω-values of the generators. In addition, we relate the ω-value of the numerical semigroup to its catenary degree.


2021 ◽  
Vol 26 (3) ◽  
Author(s):  
Sedat İLHAN

 In this paper, we will give some results about the symmetric numerical semigroups such that Sk=<7,7k+4>  where k is integer number.. Also, we will obtain Arf closure of these symmetric numerical semigroups.


Mathematics ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 557 ◽  
Author(s):  
Muhammad Ahsan Binyamin ◽  
Hafiz Muhammad Afzal Siddiqui ◽  
Nida Munawar Khan ◽  
Adnan Aslam ◽  
Yongsheng Rao

Let Γ be a numerical semigroup. We associate an undirected graph G ( Γ ) with a numerical semigroup Γ with vertex set { v i : i ∈ N \ Γ } and edge set { v i v j ⇔ i + j ∈ Γ } . In this article, we discuss the connectedness, diameter, girth, and some other related properties of the graph G ( Γ ) .


2018 ◽  
Vol 17 (11) ◽  
pp. 1850205 ◽  
Author(s):  
Dario Spirito

The set [Formula: see text] of the classes of nondivisorial ideals of a numerical semigroup [Formula: see text] can be endowed with a natural partial order induced by the set of star operations on [Formula: see text]. We study embeddings of [Formula: see text] into [Formula: see text], specializing on three families of numerical semigroups with radically different behavior.


2018 ◽  
Vol 30 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Pedro A. García-Sánchez ◽  
David Llena ◽  
Alessio Moscariello

Abstract We present a fast algorithm to compute the Delta set of a nonsymmetric numerical semigroup with embedding dimension three. We also characterize the sets of integers that are the Delta set of a numerical semigroup of this kind.


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