English

Distribution of Farey fractions with $k$-free denominators

Number Theory 2025-07-04 v2

Abstract

We investigate the distributional properties of the sequence of Farey fractions with kk-free denominators in residue classes, defined as FQ,k(m):={aq  1aqQ, gcd(a,q)=1, q is k-free & qb(modm)}.\mathscr{F}_{Q,k}^{(m)}:=\left\{\frac{a}{q}\ |\ 1\leq a\leq q\leq Q,\ \gcd(a,q)=1,\ q\ \text{is}\ k\text{-free}\ \&\ q\equiv b\pmod{m} \right\}. We show that (FQ,k(m))Q1\left(\mathscr{F}_{Q,k}^{(m)}\right)_{Q\ge 1} is equidistributed modulo one, and prove analogues of the classical results of Franel, Landau, and Niederreiter for (FQ,k(m))Q1\left(\mathscr{F}_{Q,k}^{(m)}\right)_{Q\ge 1}, particularly, deriving an equivalent form of the generalized Riemann hypothesis (GRH) for Dirichlet LL-functions in terms of the distribution of (FQ,k(m))Q1\left(\mathscr{F}_{Q,k}^{(m)}\right)_{Q\ge 1}. Beyond examining the global distribution, we also study the local statistics of these sequences. We establish formulas for all levels (k2k\ge 2) of correlation measure. Specifically, we show the existence of the limiting pair (k=2k=2) correlation function and provide an explicit expression for it. Our results are based upon the estimation of weighted Weyl sums and weighted lattice point counting in restricted domains.

Keywords

Cite

@article{arxiv.2507.00228,
  title  = {Distribution of Farey fractions with $k$-free denominators},
  author = {Bittu Chahal and Tapas Chatterjee and Sneha Chaubey},
  journal= {arXiv preprint arXiv:2507.00228},
  year   = {2025}
}