Improved bounds for the Mayer-Erdős phenomenon on similarly ordered Farey fractions

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: van Doorn, Wouter
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914014264557568
author van Doorn, Wouter
author_facet van Doorn, Wouter
contents Let $\frac{a_1}{b_1}, \frac{a_2}{b_2}, \ldots$ be the Farey fractions of order $n$. We then prove that the inequality $(a_l - a_k)(b_l - b_k) \ge 0$ holds for all $k$ and $l > k$ with $l-k \le \left(\frac{1}{12} - o(1) \right)n$, sharpening an old result by Erdős. On the other hand, we will show that for all $n \ge 4$ there are $k, l$ with $k < l < k + \frac{n}{4} + 5$ for which the product $(a_l - a_k)(b_l - b_k)$ is negative.
format Preprint
id arxiv_https___arxiv_org_abs_2509_00121
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Improved bounds for the Mayer-Erdős phenomenon on similarly ordered Farey fractions
van Doorn, Wouter
Number Theory
Let $\frac{a_1}{b_1}, \frac{a_2}{b_2}, \ldots$ be the Farey fractions of order $n$. We then prove that the inequality $(a_l - a_k)(b_l - b_k) \ge 0$ holds for all $k$ and $l > k$ with $l-k \le \left(\frac{1}{12} - o(1) \right)n$, sharpening an old result by Erdős. On the other hand, we will show that for all $n \ge 4$ there are $k, l$ with $k < l < k + \frac{n}{4} + 5$ for which the product $(a_l - a_k)(b_l - b_k)$ is negative.
title Improved bounds for the Mayer-Erdős phenomenon on similarly ordered Farey fractions
topic Number Theory
url https://arxiv.org/abs/2509.00121