English

An asymptotic Robin inequality

Number Theory 2016-02-11 v1

Abstract

The conjectured Robin inequality for an integer n>7!n>7! is σ(n)<eγnloglogn,\sigma(n)<e^\gamma n \log \log n, where γ\gamma denotes Euler constant, and σ(n)=dnd\sigma(n)=\sum_{d | n} d . Robin proved that this conjecture is equivalent to Riemann hypothesis (RH). Writing D(n)=eγnloglognσ(n),D(n)=e^\gamma n \log \log n-\sigma(n), and d(n)=D(n)n,d(n)=\frac{D(n)}{n}, we prove unconditionally that lim infnd(n)=0.\liminf_{n \rightarrow \infty} d(n)=0. The main ingredients of the proof are an estimate for Chebyshev summatory function, and an effective version of Mertens third theorem due to Rosser and Schoenfeld. A new criterion for RH depending solely on lim infnD(n)\liminf_{n \rightarrow \infty}D(n) is derived.

Keywords

Cite

@article{arxiv.1602.03384,
  title  = {An asymptotic Robin inequality},
  author = {Patrick Solé and Yuyang Zhu},
  journal= {arXiv preprint arXiv:1602.03384},
  year   = {2016}
}

Comments

5 pages

R2 v1 2026-06-22T12:47:37.412Z