English

Gaps in the complex Farey sequence of an imaginary quadratic number field

Number Theory 2025-04-15 v2 Dynamical Systems

Abstract

Given an imaginary quadratic number field KK with ring of integers OK\mathcal{O}_K, we are interested in the asymptotic \emph{distance to nearest neighbour} (or \emph{gap}) statistic of complex Farey fractions pq\frac{p}{q}, with p,qOKp,q \in \mathcal{O}_K and 0<qT0<|q|\leq T, as TT \to \infty. Reformulating this problem in a homogeneous dynamical setting, we follow the approach of J. Marklof for real Farey fractions with several variables (2013) and adapt a joint equidistribution result in the real 33-dimensional hyperbolic space of J. Parkkonen and F. Paulin (2023) to derive the existence of a probability measure describing this asymptotic gap statistic. We obtain an integral formula for the associated cumulative distribution function, and use geometric arguments to find an explicit estimate for its tail distribution in the cases of Gaussian and Eisenstein fractions.

Keywords

Cite

@article{arxiv.2407.04380,
  title  = {Gaps in the complex Farey sequence of an imaginary quadratic number field},
  author = {Rafael Sayous},
  journal= {arXiv preprint arXiv:2407.04380},
  year   = {2025}
}

Comments

20 pages, 6 figures