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Hauptverfasser: Daans, Nicolas, Kala, Vítězslav, Man, Siu Hang
Format: Preprint
Veröffentlicht: 2023
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Online-Zugang:https://arxiv.org/abs/2308.16721
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author Daans, Nicolas
Kala, Vítězslav
Man, Siu Hang
author_facet Daans, Nicolas
Kala, Vítězslav
Man, Siu Hang
contents We show that if a universal quadratic form exists over an infinite degree, totally real extension of the field of rationals $\mathbb{Q}$, then the set of totally positive integers in the extension does not have the Northcott property. In particular, this implies that no universal form exists over the compositum of all totally real Galois fields of a fixed prime degree over $\mathbb{Q}$. Further, by considering the existence of infinitely many square classes of totally positive units, we show that no classical universal form exists over the compositum of all such fields of degree $3d$ (for each fixed odd integer $d$).
format Preprint
id arxiv_https___arxiv_org_abs_2308_16721
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Universal quadratic forms and Northcott property of infinite number fields
Daans, Nicolas
Kala, Vítězslav
Man, Siu Hang
Number Theory
11E12 (Primary) 11E20, 11G50, 11H55, 11R04, 11R20, 11R80 (Secondary)
We show that if a universal quadratic form exists over an infinite degree, totally real extension of the field of rationals $\mathbb{Q}$, then the set of totally positive integers in the extension does not have the Northcott property. In particular, this implies that no universal form exists over the compositum of all totally real Galois fields of a fixed prime degree over $\mathbb{Q}$. Further, by considering the existence of infinitely many square classes of totally positive units, we show that no classical universal form exists over the compositum of all such fields of degree $3d$ (for each fixed odd integer $d$).
title Universal quadratic forms and Northcott property of infinite number fields
topic Number Theory
11E12 (Primary) 11E20, 11G50, 11H55, 11R04, 11R20, 11R80 (Secondary)
url https://arxiv.org/abs/2308.16721