Real quadratic fields with a universal quadratic form of given rank have density zero

Fuente: arXiv
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Main Authors: Kala, Vitezslav, Yatsyna, Pavlo, Żmija, Błażej
Format: Preprint
Published: 2023
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author Kala, Vitezslav
Yatsyna, Pavlo
Żmija, Błażej
author_facet Kala, Vitezslav
Yatsyna, Pavlo
Żmija, Błażej
contents We prove an explicit upper bound on the number of real quadratic fields that admit a universal quadratic form of a given rank, thus establishing a density zero statement. More generally, we obtain such a result for totally positive definite quadratic lattices that represent all the multiples of a given rational integer. Our main tools are short vectors in quadratic lattices combined with an estimate for the number of periodic continued fractions with bounded coefficients.
format Preprint
id arxiv_https___arxiv_org_abs_2302_12080
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Real quadratic fields with a universal quadratic form of given rank have density zero
Kala, Vitezslav
Yatsyna, Pavlo
Żmija, Błażej
Number Theory
11A55, 11E12, 11E20, 11H55, 11R11, 11R80
We prove an explicit upper bound on the number of real quadratic fields that admit a universal quadratic form of a given rank, thus establishing a density zero statement. More generally, we obtain such a result for totally positive definite quadratic lattices that represent all the multiples of a given rational integer. Our main tools are short vectors in quadratic lattices combined with an estimate for the number of periodic continued fractions with bounded coefficients.
title Real quadratic fields with a universal quadratic form of given rank have density zero
topic Number Theory
11A55, 11E12, 11E20, 11H55, 11R11, 11R80
url https://arxiv.org/abs/2302.12080