English

Bertrand's Postulate for Carmichael Numbers

Number Theory 2023-10-19 v2

Abstract

Alford, Granville, and Pomerance proved that there are infinitely many Carmichael numbers. In the same paper, they ask if a statement analogous to Bertrand's postulate could be proven for Carmichael numbers. In this paper, we answer this question, proving the stronger statement that for all δ>0\delta>0 and xx sufficiently large in terms of δ\delta, there exist at least elogx(loglogx)2+δe^{\frac{\log x}{(\log\log x)^{2+\delta}}} Carmichael numbers between xx and x+x(logx)12+δx+\frac{x}{(\log x)^{\frac{1}{2+\delta}}}.

Cite

@article{arxiv.2111.06963,
  title  = {Bertrand's Postulate for Carmichael Numbers},
  author = {Daniel Larsen},
  journal= {arXiv preprint arXiv:2111.06963},
  year   = {2023}
}

Comments

27 pages; corrected minor issues

R2 v1 2026-06-24T07:36:53.754Z