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NON-DIOPHANTINE SETS IN RINGS OF FUNCTIONS

Published online by Cambridge University Press:  12 November 2025

NATALIA GARCIA-FRITZ
Affiliation:
DEPARTMENT OF MATHEMATICS PONTIFICIA UNIVERSIDAD CATÓLICA DE CHILE CHILE E-mail: natalia.garcia@uc.cl
HECTOR PASTEN*
Affiliation:
DEPARTMENT OF MATHEMATICS PONTIFICIA UNIVERSIDAD CATÓLICA DE CHILE CHILE E-mail: natalia.garcia@uc.cl
THANASES PHEIDAS
Affiliation:
DEPARTMENT OF MATHEMATICS UNIVERSITY OF CRETE GREECE E-mail: pheidas@uoc.gr

Abstract

Except for a limited number of cases, a complete classification of the Diophantine (i.e., positive existentially definable) sets of polynomial rings and fields of rational functions seems out of reach at present. We contribute to this problem by proving that several natural sets and relations over these structures are not Diophantine. For instance, we show that the relation of equality of degrees is not Diophantine over the field of complex rational functions in one variable and, in the same structure, we show that certain family of relations that approximates the valuation ring at infinity is not Diophantine either.

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© The Author(s), 2025. Published by Cambridge University Press on behalf of The Association for Symbolic Logic

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References

REFERENCES

Abramovich, D., Birational geometry for number theorists , Arithmetic Geometry, Clay Mathematics Proceedings, 8, American Mathematical Society, Providence, RI, 2009, pp. 335373.Google Scholar
Abramovich, D. and Várilly-Alvarado, A., Campana points, Vojta’s conjecture, and level structures on semistable abelian varieties . Journal de Théorie des Nombres de Bordeaux, vol. 30 (2018), no. 2, pp. 525532.Google Scholar
Anscombe, S., Existentially generated subfields of large fields . Journal of Algebra, vol. 517 (2019), pp. 7894.Google Scholar
Browning, T. D. and Van Valckenborgh, K., Sums of three squareful numbers . Experimental Mathematics, vol. 21 (2012), no. 2, pp. 204211.Google Scholar
Browning, T. D. and Yamagishi, S., Arithmetic of higher-dimensional orbifolds and a mixed waring problem . Mathematische Zeitschrift, vol. 299 (2021), nos. 1–2, pp. 10711101.Google Scholar
Campana, F., Fibres multiples Sur les surfaces: Aspects geométriques, hyperboliques et arithmétiques . Manuscripta Mathematica, vol. 117 (2005), no. 4, pp. 429461.Google Scholar
Davis, M., Putnam, H., and Robinson, J., The decision problem for exponential diophantine equations . Annals of Mathematics (2), vol. 74 (1961), pp. 425436.Google Scholar
Demeyer, J., Recursively enumerable sets of polynomials over a finite field are Diophantine . Inventiones Mathematicae, vol. 170 (2007), no. 3, pp. 655670.Google Scholar
Demeyer, J., Diophantine sets of polynomials over number fields . Proceedings of the American Mathematical Society, vol. 138 (2010), no. 8, pp. 27152728.Google Scholar
Denef, J., The Diophantine problem for polynomial rings and fields of rational functions . Transactions of the American Mathematical Society, vol. 242 (1978), pp. 391399.Google Scholar
Denef, J., Diophantine sets over $\mathbb{Z}\left[T\right]$ . Proceedings of the American Mathematical Society, vol. 69 (1978), no. 1, pp. 148150.Google Scholar
Fehm, A., Subfields of ample fields. Rational maps and definability . Journal of Algebra, vol. 323 (2010), no. 6, pp. 17381744.Google Scholar
Garcia-Fritz, N., On the conjectures of Vojta and Campana over function fields with explicit exceptional sets, preprint, 2022. https://arxiv.org/abs/2203.00626Google Scholar
Garcia-Fritz, N. and Pasten, H., A Diophantine definition of the constants in $\mathbb{Q}(z)$ . Proceedings of the American Mathematical Society, vol. 153 (2025), no. 2, pp. 523534.Google Scholar
Koenigsmann, J., Defining transcendentals in function fields . The Journal of Symbolic Logic, vol. 67 (2002), no. 3, pp. 947956.Google Scholar
Koenigsmann, J., Defining $\mathbb{Z}$ in $\mathbb{Q}$ . Annals of Mathematics (2), vol. 183 (2016), no. 1, pp. 7393.Google Scholar
Kollár, J., Diophantine subsets of function fields of curves . Algebra Number Theory, vol. 2 (2008), no. 3, pp. 299311.Google Scholar
Kuwata, M., The canonical height and elliptic surfaces . Journal of Number Theory, vol. 36 (1990), no. 2, pp. 201211.Google Scholar
Matiyasevich, J., The Diophantineness of enumerable sets. (Russian) . Doklady Akademii Nauk SSSR, vol. 191 (1970), pp. 279282.Google Scholar
Moret-Bailly, L., Sur la définissabilité existentielle de la non-nullité dans les anneaux . Algebra Number Theory, vol. 1 (2007), no. 3, pp. 331346.Google Scholar
Oguiso, K. and Shioda, T., The Mordell-Weil lattice of a rational elliptic surface . Commentarii Mathematici Universitatis Sancti Pauli, vol. 40 (1991), no. 1, pp. 8399.Google Scholar
Pasten, H., Notes on the DPRM property for listable structures . Journal of Symbolic Logic, vol. 87 (2022), no. 1, pp. 273312.Google Scholar
Pheidas, T. and Zahidi, K., Undecidability of existential theories of rings and fields: A survey , Hilbert’s Tenth Problem: Relations with Arithmetic and Algebraic Geometry (Ghent, 1999), Contemporary Mathematics, 270, American Mathematical Society, Providence, 2000, pp. 49105.Google Scholar
Pieropan, M., Smeets, A., Tanimoto, S., and Várilly-Alvarado, A., Campana points of bounded height on vector group compactifications . Proceedings of the London Mathematical Society (3), vol. 123 (2021), no. 1, pp. 57101.Google Scholar
Poonen, B., The set of nonsquares in a number field is Diophantine . Mathematical Research Letters, vol. 16 (2009), no. 1, pp. 165170.Google Scholar
Pop, F., Little survey on large fields–old & new , Valuation Theory in Interaction, EMS Series of Congress Reports, European Mathematical Society, Zürich, 2014, pp. 432463.Google Scholar
De Rasis, J., First-order definability of affine Campana points in the projective line over a number field, preprint, 2024. arXiv:2401.16354.Google Scholar
Rousseau, E., Turchet, A., and Wang, J. T.-Y., Nonspecial varieties and generalised Lang-Vojta conjectures . Forum of Mathematics Sigma, vol. 9 (2021), Article no. e11, 29 pp.Google Scholar
Schütt, M. and Shioda, T., Elliptic surfaces , Algebraic Geometry in East Asia-Seoul 2008, Advanced Studies in Pure Mathematics, 60, The Mathematical Society of Japan, Tokyo, 2010, pp. 51160.Google Scholar
Silverman, J., Computing heights on elliptic curves . Mathematics of Computation, vol. 51 (1988), no. 183, pp. 339358.Google Scholar
Van Valckenborgh, K., Squareful numbers in hyperplanes . Algebra Number Theory, vol. 6 (2012), no. 5, pp. 10191041.Google Scholar
Vojta, P., Diophantine approximation and Nevanlinna theory , Arithmetic Geometry, Advanced Studies in Pure Mathematics, 2009, Springer, Berlin, 2011, pp. 111224.Google Scholar