Abstract
A common tool in the theory of numerical semigroups is to interpret a desired class of semigroups as the lattice points in a rational polyhedron in order to leverage computational and enumerative techniques from polyhedral geometry. Most arguments of this type make use of a parametrization of numerical semigroups with fixed multiplicity m in terms of their m-Apéry sets, giving a representation called Kunz coordinates which obey a collection of inequalities defining the Kunz polyhedron. In this work, we introduce a new class of polyhedra describing numerical semigroups in terms of a truncated addition table of their positive sporadic elements. Applying a classical theorem of Ehrhart to slices of these polyhedra, we prove that the number of numerical semigroups with n sporadic elements and Frobenius number f is polynomial up to periodicity, or quasi-polynomial, as a function of f for fixed n. We also generalize this approach to higher dimensions to demonstrate quasi-polynomial growth of the number of affine semigroups with a fixed number of elements, and all gaps, contained in an integer dilation of a fixed polytope.
Similar content being viewed by others
Notes
The semigroups described by the addition table \(\tau _0\) are the so-called elementary numerical semigroups (with n positive sporadic elements), defined as the semigroups with Frobenius number at most twice the multiplicity.
References
Alhajjar, E., Russell, T., Steward, M.: Numerical semigroups and Kunz polytopes. Semigroup Forum 99(1), 153–168 (2019)
Backelin, J.: On the number of semigroups of natural numbers. Math. Scand. 66(2), 197–215 (1990)
Beck, M., Ehrenborg, R.: Ehrhart–Macdonald reciprocity extended (2005). arXiv:math/0504230 [math.CO]
Blanco, V., García-Sánchez, P.A., Puerto, J.: Counting numerical semigroups with short generating functions. Int. J. Algebra Comput. 21(07), 1217–1235 (2011)
Blanco, V., Rosales, J.C.: The set of numerical semigroups of a given genus. Semigroup Forum 85(2), 255–267 (2012)
Blanco, V., Rosales, J.C.: On the enumeration of the set of numerical semigroups with fixed Frobenius number. Comput. Math. Appl. 63(7), 1204–1211 (2012)
Blanco, V., Rosales, J.C.: The tree of irreducible numerical semigroups with fixed Frobenius number. Forum Math. 25(6), 1249–1261 (2013)
Branco, M.B., Ojeda, I., Rosales, J.C.: The set of numerical semigroups of a given multiplicity and Frobenius number. Port. Math. 78(2), 147–167 (2021)
Bras-Amorós, M.: Fibonacci-like behavior of the number of numerical semigroups of a given genus. Semigroup Forum 76(2), 379–384 (2008)
Bras-Amorós, M.: Bounds on the number of numerical semigroups of a given genus. J. Pure Appl. Algebra 213(6), 997–1001 (2009)
Bras-Amorós, M., Bulygin, S.: Towards a better understanding of the semigroup tree. Semigroup Forum 79(3), 561–574 (2009)
Ehrhart, E.: Sur les polyèdres rationnels homothétiques à \(n\) dimensions. C. R. Acad. Sci. Paris 254, 616–618 (1962)
Ehrhart, E.: Sur un probleme de géométrie diophantienne linéaire. I. Polyedres et réseaux. J. Reine Angew. Math. 226, 1–29 (1967)
Elizalde, S.: Improved bounds on the number of numerical semigroups of a given genus. J. Pure Appl. Algebra 214(10), 1862–1873 (2010)
García-García, J.I., Marín-Aragón, D., Vigneron-Tenorio, A.: An extension of Wilf’s conjecture to affine semigroups. Semigroup Forum 96(2), 396–408 (2018)
Gubeladze, J., Bruns, W.: Polytopes, Rings, and K-Theory. Springer Monographs in Mathematics. Springer, New York (2009)
Kaplan, N.: Counting numerical semigroups. Am. Math. Mon. 124(9), 862–875 (2017)
Kaplan, N.: Counting numerical semigroups by genus and some cases of a question of Wilf. J. Pure Appl. Algebra 216(5), 1016–1032 (2012)
Kunz, E.: Über die Klassifikation Numerischer Halbgruppen. Regensburger mathematische Schriften. Fakultät für Mathematik der Universität Regensburg (1987)
Li, S.: Counting numerical semigroups by Frobenius number, multiplicity, and depth (2022). arXiv:2208.14587 [math.CO]
MacDonald, I.G.: Polynomials associated with finite cell-complexes. J. Lond. Math. Soc. s2–4(1), 181–192 (1971)
Robbiano, L.: On the theory of graded structures. J. Symb. Comput. 2(2), 139–170 (1986)
Rosales, J.C.: On numerical semigroups. Semigroup Forum 52(3), 307–318 (1996)
Rosales, J.C., García-Sánchez, P.A., García-García, J.I., Branco, M.B.: Systems of inequalities and numerical semigroups. J. Lond. Math. Soc. 65(03), 611–623 (2002)
Singhal, D.: Distribution of genus among numerical semigroups with fixed Frobenius number. Semigroup Forum 104(3), 704–723 (2022)
Zhai, A.: Fibonacci-like growth of numerical semigroups of a given genus. Semigroup Forum 86(3), 634–662 (2013)
Zhao, Y.: Constructing numerical semigroups of a given genus. Semigroup Forum 80(2), 242–254 (2010)
Ziegler, G.M.: Lectures on Polytopes. Graduate Texts in Mathematics, vol. 152. Springer, New York (1995)
Acknowledgements
We thank Nathan Kaplan for providing detailed feedback on our first draft, including suggesting additional connections to the semigroup literature and motivating the probabilistic interpretation of Corollary 2 given by Corollary 3. We also thank the anonymous referee for their comments and suggestions, which helped to improve the presentation of the paper.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Nathan Kaplan.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
DiPasquale, M., Gillespie, B.R. & Peterson, C. Quasi-polynomial growth of numerical and affine semigroups with constrained gaps. Semigroup Forum 107, 60–78 (2023). https://doi.org/10.1007/s00233-023-10366-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00233-023-10366-x