On the length of an interval that contains distinct multiples of the first $n$ positive integers
Wouter van Doorn
TL;DR
The paper settles the Erdős-Pomerance conjecture by showing there exist intervals of length $\frac{0.36\,n\log n}{\log\log n}$ that do not contain distinct multiples of $1,\dots,n$, thereby establishing a nontrivial growth rate for gaps between such multiples. The proof hinges on a fundamental inequality $kn+f(kn,kn)\le k^2n+f(n,k^2n)$, together with the best-known bounds for $f(n,n)$, and a carefully chosen parameter $k=\lceil 0.6\sqrt{\frac{\log n}{\log\log n}}\rceil$ to separate $f(n,n)$ from larger $f(n,m)$. This yields a positive lower bound on $\max_m f(n,m)-f(n,n)$, confirming the conjecture and advancing our understanding of divisibility-structure gaps in intervals. The result provides a concrete asymptotic rate for constructing long intervals void of distinct multiples of the first $n$ integers and contributes to extremal problems in additive number theory.
Abstract
Confirming a conjecture by Erd\H os and Pomerance, we prove that there exist intervals of length $\frac{cn\log n}{\log \log n}$ that do not contain distinct multiples of $1, 2, \ldots, n$.
