English

A lower bound on the mean value of the Erd\H{o}s-Hooley Delta function

Number Theory 2024-05-24 v2

Abstract

We give an improved lower bound for the average of the Erd\H{o}s-Hooley function Δ(n)\Delta(n), namely nxΔ(n)εx(loglogx)1+ηε\sum_{n\le x} \Delta(n) \gg_\varepsilon x(\log\log x)^{1+\eta-\varepsilon} for all x100x\geqslant100 and any fixed ε\varepsilon, where η=0.3533227\eta = 0.3533227\dots is an exponent previously appearing in work of Green and the first two authors. This improves on a previous lower bound of xloglogx\gg x \log\log x of Hall and Tenenbaum, and can be compared to the recent upper bound of x(loglogx)11/4x (\log\log x)^{11/4} of the second and third authors.

Keywords

Cite

@article{arxiv.2308.11987,
  title  = {A lower bound on the mean value of the Erd\H{o}s-Hooley Delta function},
  author = {Kevin Ford and Dimitris Koukoulopoulos and Terence Tao},
  journal= {arXiv preprint arXiv:2308.11987},
  year   = {2024}
}

Comments

15 pages. Added remarks in the end of page 3; added references [3] and [9]. Final version, to appear in Proc. London Math. Soc