Abstract
In this paper we use an elementary approach by using numerical semigroups (specifically, those with two generators) to give a formula for the number of integral points inside a right-angled triangle with rational vertices. This is the basic case for computing the number of integral points inside a rational (not necessarily convex) polygon.
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Notes
Throughout this paper we will call a point \(P \in {\mathbb {R}}^2\) integral if its coordinates lie in \({\mathbb {Z}}^2\), and similarly P will be called rational if \(P \in {\mathbb {Q}}^2\).
References
Pick, G.A.: Geometrisches zur Zahlenlehre. Sitzungsber. Lotos (Prague) 19, 311–319 (1889)
Hardy, G.H., Littlewood, J.E.: Some problems of Diophantine approximation: the lattice-points of a right-angled triangle. Abh. Math. Sem. Univ. Hambg. 1, 211–248 (1922)
Ehrhart, E.: Sur les polyèdres rationnels homothétiques à \(n\) dimensions. C. R. Acad. Sci. Paris 254, 616–618 (1962)
Louis, J.M.: Lattice points in a tetrahedron and generalized Dedekind sums. J. Indian Math. Soc. (N.S.) 15, 41–46 (1951)
Pommersheim, J.E.: Toric varieties, lattice points and Dedekind sums. Math. Ann. 295, 1–24 (1993)
Reeve, J.E.: On the volume of the lattice polyhedra. Proc. Lond. Math. Soc. 7, 378–395 (1957)
Beck, M., Robins, S.: Computing the continuous discretely. Integer-point enumeration in polyhedra. Springer, New York (2007)
Beck, M., Robins, S.: Explicit and efficient formulas for the lattice point count inside rational polygons using Dedekind-Rademacher sums. Discrete Comput. Geom. 27, 443–459 (2002)
Barvinok, A.I.: Integer points in polyhedra. Zurich Lectures in Advanced Mathematics. European Mathematical Society (EMS), Zürich (2008)
Barvinok, A.I.: A polynomial time algorithm for counting integral points in polyhedra when the dimension is fixed. Math. Oper. Res. 19, 769–779 (1994)
Lin, K.P., Yau, S.T.: Analysis of sharp polynomial upper estimate of number of positive integral points in 4-dimensional tetrahedra. J. Reine Angew. Math. 547, 191–205 (2002)
Lin, K.P., Yau, S.T.: Analysis of sharp polynomial upper estimate of number of positive integral points in 5-dimensional tetrahedra. J. Number Theory 93, 207–234 (2002)
Lin, K.P., Yau, S.S.T.: Counting the number of integral points in general \(n\)-dimensional tetrahedra and Bernoulli polynomials. Can. Math. Bull. 24, 229–241 (2003)
Wang, X., Yau, S.S.T.: On the GLY conjecture of upper estimate of positive integral points in real right-angled simplices. J. Number Theory 122, 184–210 (2007)
Xu, Y.J., Yau, S.S.T.: A sharp estimate of number of integral points in a tetrahedron. J. Reine Angew. Math. 423, 199–219 (1992)
Xu, Y.J., Yau, S.S.T.: Durfee conjecture and coordinate free characterization of homogeneous singularities. J. Differ. Geom. 37, 375–396 (1993)
Xu, Y.J., Yau, S.S.T.: A sharp estimate of number of integral points in a 4-dimensional tetrahedra. J. Reine Angew. Math. 473, 1–23 (1996)
Yau, S.S.T., Zhang, L.: An upper estimate of integral points in real simplices with an application to singularity theory. Math. Res. Lett. 13, 911–921 (2006)
Márquez–Campos, G., Tornero, J.M.: Characterization of gaps and elements of a numerical semigroup using Groebner bases. In: Trends in Number Theory. Contemporary Mathematics, vol. 649, p. 139. American Mathematical Society, Providence, RI (2015)
Ramírez Alfonsín, J.L.: Gaps in semigroups. Discrete Math. 308, 4177–4184 (2008)
García-Sánchez, P.A., Rosales, J.C.: Numerical semigroups. Springer, New York (2009)
Ramírez Alfonsín, J.L.: The Diophantine Frobenius problem. Oxford University Press, Oxford (2005)
Berg, M.D, Kreveld, M.V., Overmars, M., Schwarzkopf, O.: Computational geometry (2nd revised ed.). Springer, New York (2009)
Kirkpatrick, D.G., Klawe, M.M., Tarjan, R.E.: Polygon triangulation in \({\cal O}(n \log \log n)\) time with simple data structures. Discrete Comput. Geom. 7, 329–346 (1992)
Popoviciou, T.: Asupra unei probleme de patitie a numerelor. Acad. Repub. Pop. Romane Filiala Cluj Studii si cercetari stiintifice 4, 7–58 (1953)
Brown, T.C., Chou, W.S., Shiue, P.J.: On the partition function of a finite set. Australas. J. Comb. 27, 193–204 (2003)
Acknowledgments
The authors warmly acknowledge the help and advice of J. C. Rosales.
The final stage of this work was completed during a stay of the first author in the Institut Montpelliérain Alexander Grothendieck, Université de Montpellier, during the spring term of 2013, thanks to the Grant P08–FQM–3894 (Junta de Andalucía).
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Communicated by Fernando Torres.
Guadalupe Márquez-Campos and José M. Tornero were partially supported by the Grant FQM–218 and P12–FQM–2696 (FEDER and FSE). The Jorge L. Ramírez-Alfonsín was supported by ANR TEOMATRO Grant ANR-10-BLAN 0207 and Grant ECOS-Nord M13M01.
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Márquez-Campos, G., Ramírez-Alfonsín, J.L. & Tornero, J.M. Integral points in rational polygons: a numerical semigroup approach. Semigroup Forum 94, 123–138 (2017). https://doi.org/10.1007/s00233-016-9820-y
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DOI: https://doi.org/10.1007/s00233-016-9820-y