English

$p$-adic quotient sets II: quadratic forms

Number Theory 2021-02-05 v2

Abstract

For A{1,2,}A \subseteq \{1,2,\ldots\}, we consider R(A)={a/a:a,aA}R(A) = \{a/a' : a,a' \in A\}. If AA is the set of nonzero values assumed by a quadratic form, when is R(A)R(A) dense in the pp-adic numbers? We show that for a binary quadratic form QQ, R(A)R(A) is dense in Qp\mathbb{Q}_{p} if and only if the discriminant of QQ is a nonzero square in Qp\mathbb{Q}_{p}, and for a quadratic form in at least three variables, R(A)R(A) is always dense in Qp\mathbb{Q}_{p}. This answers a question posed by several authors in 2017.

Keywords

Cite

@article{arxiv.1812.11200,
  title  = {$p$-adic quotient sets II: quadratic forms},
  author = {Christopher Donnay and Stephan Ramon Garcia and Jeremy Rouse},
  journal= {arXiv preprint arXiv:1812.11200},
  year   = {2021}
}

Comments

14 pages

R2 v1 2026-06-23T06:58:24.297Z