Quartic Rational Diophantine Quadruples and the Euler Surface

Fuente: arXiv
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Main Authors: Andrašek, Alen, Kazalicki, Matija, Vlah, Domagoj
Format: Preprint
Published: 2026
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author Andrašek, Alen
Kazalicki, Matija
Vlah, Domagoj
author_facet Andrašek, Alen
Kazalicki, Matija
Vlah, Domagoj
contents We prove that there exist infinitely many quartic rational Diophantine quadruples, that is, sets of four pairwise distinct nonzero rational numbers whose pairwise products increased by 1 are fourth powers in Q. To the best of our knowledge, no examples of such quadruples were previously known. Our construction is motivated by computer experiments and leads naturally to the classical Euler surface E:X^4+Y^4=Z^4+W^4. We show that every rational point on a suitable Zariski-open subset of E yields a quartic rational Diophantine quadruple, thereby obtaining a rational map from the Euler surface to the parameter space of quartic quadruples. In particular, Euler's classical parametrization produces the first explicit infinite family of quartic rational Diophantine quadruples. We also explain that the same mechanism extends to arbitrary exponents k>1, with the Euler surface replaced by the Fermat--Euler surface E_k:X^k+Y^k=Z^k+W^k. For even k, every rational point on a suitable open subset of E_k gives rise to a kth power rational Diophantine quadruple, while for odd k one obtains such quadruples on the locus where W/Z is a square.
format Preprint
id arxiv_https___arxiv_org_abs_2604_19140
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Quartic Rational Diophantine Quadruples and the Euler Surface
Andrašek, Alen
Kazalicki, Matija
Vlah, Domagoj
Number Theory
We prove that there exist infinitely many quartic rational Diophantine quadruples, that is, sets of four pairwise distinct nonzero rational numbers whose pairwise products increased by 1 are fourth powers in Q. To the best of our knowledge, no examples of such quadruples were previously known. Our construction is motivated by computer experiments and leads naturally to the classical Euler surface E:X^4+Y^4=Z^4+W^4. We show that every rational point on a suitable Zariski-open subset of E yields a quartic rational Diophantine quadruple, thereby obtaining a rational map from the Euler surface to the parameter space of quartic quadruples. In particular, Euler's classical parametrization produces the first explicit infinite family of quartic rational Diophantine quadruples. We also explain that the same mechanism extends to arbitrary exponents k>1, with the Euler surface replaced by the Fermat--Euler surface E_k:X^k+Y^k=Z^k+W^k. For even k, every rational point on a suitable open subset of E_k gives rise to a kth power rational Diophantine quadruple, while for odd k one obtains such quadruples on the locus where W/Z is a square.
title Quartic Rational Diophantine Quadruples and the Euler Surface
topic Number Theory
url https://arxiv.org/abs/2604.19140