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arXiv · 1601.07337

Numerical semigroups II: pseudo-symmetric AA-Semigroups

Ignacio García-Marco·Jorge L. Ramírez Alfonsín·Oystein J. Rodseth
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Abstract

This paper is a continuation of the paper "Numerical Semigroups: Ap\'ery Sets and Hilbert Series". We consider the general numerical AA-semigroup, i.e., semigroups consisting of all non-negative integer linear combinations of relatively prime positive integers of the form $a,a+d,a+2d,\dots,a+kd,c$. We first prove that, in contrast to arbitrary numerical semigroups, there exists an upper bound for the type of AA-semigroups that only depends on the number of generators of the semigroup. We then present two characterizations of pseudo-symmetric AA-semigroups. The first one leads to a polynomial time algorithm to decide whether an AA-semigroup is pseudo-symmetric. The second one gives a method to construct pseudo-symmetric AA-semigroups and provides explicit families of pseudo-symmetric semigroups with arbitrarily large number of generators.

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Ignacio García-Marco, Jorge L. Ramírez Alfonsín, Oystein J. Rodseth. 2016-01-27. Numerical semigroups II: pseudo-symmetric AA-Semigroups. https://arxiv.org/abs/1601.07337

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