English

Martingale central limit theorem for random multiplicative functions

Number Theory 2024-06-07 v2 Probability

Abstract

Let α\alpha be a Steinhaus or a Rademacher random multiplicative function. For a wide class of multiplicative functions ff we show that the sum nxα(n)f(n)\sum_{n \le x}\alpha(n) f(n), normalised to have mean square 11, has a non-Gaussian limiting distribution. More precisely, we establish a generalised central limit theorem with random variance determined by the total mass of a random measure associated with αf\alpha f. Our result applies to dzd_z, the zz-th divisor function, as long as zz is strictly between 00 and 12\tfrac{1}{\sqrt{2}}. Other examples of admissible ff-s include any multiplicative indicator function with the property that f(p)=1f(p)=1 holds for a set of primes of density strictly between 00 and 12\tfrac{1}{2}.

Keywords

Cite

@article{arxiv.2405.20311,
  title  = {Martingale central limit theorem for random multiplicative functions},
  author = {Ofir Gorodetsky and Mo Dick Wong},
  journal= {arXiv preprint arXiv:2405.20311},
  year   = {2024}
}

Comments

42 pages, 2 figures. Typos fixed, abstract and discussion of previous works updated. Codes for simulation experiment available on authors' personal page; comments are still welcome

R2 v1 2026-06-28T16:47:35.667Z