English

On the distribution of very short character sums

Number Theory 2025-12-03 v1 Probability

Abstract

We establish a central limit theorem of (1/hp)X<nX+hp(np)(1/\sqrt{h_p})\sum_{X< n \leq X+h_p}\big(\tfrac{n}{p}\big) for almost all the primes pp, with XX uniformly random in [g(p)][g(p)], g(p)g(p) an arbitrary divergent function growing slower than any power of pp, provided (loghp)/(logg(p))0,hp(\log h_p)/(\log g(p))\rightarrow 0, \, h_p \rightarrow \infty as pp \rightarrow \infty. This improves the recent results of Basak, Nath and Zaharescu, who established this for g(p)=(logp)A,A>1g(p) = (\log p)^A, A>1. We also use the best currently available tools to expand the original central limit theorem of Davenport and Erd\H{o}s for all the primes to a shorter interval of starting points. In this paper we exploit a Selberg's sieve argument, recently used by Harper, an intersection result due to Evertse and Silverman and some consequences of the Weil bound on general character sums.

Keywords

Cite

@article{arxiv.2512.02915,
  title  = {On the distribution of very short character sums},
  author = {Paweł Nosal},
  journal= {arXiv preprint arXiv:2512.02915},
  year   = {2025}
}

Comments

16 pages. Comments welcome