English

On numbers satisfying Robin's inequality, properties of the next counterexample and improved specific bounds

Number Theory 2020-05-20 v1

Abstract

Define s(n):=n1σ(n)s (n) := n^{- 1} \sigma (n) (σ(n):=dnd)\sigma (n):=\sum_{d|n}d ) and ω(n)\omega(n) is the number of prime divisors of nn. One of the properties of ss plays a central role: s(pa)>s(qb)s (p^a) > s (q^b) if p<qp < q are prime numbers, with no special condition on a,ba, b other than a,b1a, b \geqslant 1. This result, combined with the Multiplicity Permutation theorem, will help us establish properties of the next counterexample (say cc) to Robin's inequality s(n)<eγloglogns (n) < e^{\gamma} \log \log n. The number cc is superabundant, and ω(c)\omega(c) must be greater than a number close to one billion. In addition, the ratio pω(c)/logcp_{\omega (c)} / \log c has a lower and upper bound. At most ω(c)/14\omega(c)/14 multiplicity parameters are greater than 11. Last but not least, we apply simple methods to sharpen Robin's inequality for various categories of numbers.

Keywords

Cite

@article{arxiv.2005.09307,
  title  = {On numbers satisfying Robin's inequality, properties of the next counterexample and improved specific bounds},
  author = {Robert Vojak},
  journal= {arXiv preprint arXiv:2005.09307},
  year   = {2020}
}