On variants of Chowla's conjecture
Krishnarjun Krishnamoorthy
TL;DR
This work investigates d-point correlations of completely multiplicative {±1}-valued functions by studying shifted convolution sums Λ_P^H(n) and their natural densities κ_P^H. The authors prove a finite-P multiplicative formula κ_P^H = ∏_{p∈P}(1−2η_p^H) with η_p^H = d/(p+1) for non-exceptional primes, and extend this to small infinite P via a limiting argument, along with a rigidity result that prevents nontrivial P from yielding |κ_P^H|=1. A second main theorem provides a strong constraint on possible values of κ_P^H using combinatorial and two-point correlation arguments, and the spectrum Γ_H of densities is characterized through α_H = inf_p (1−2η_p^H). Groundwork and lemmas on the structure of the N_P^H sets and the algebra A_P underpin these results, while connections to Matomäki–Radziwiłł’s two-point results and Wintner–Wirsing-type density formulas situate the work within the broader landscape of Chowla-type conjectures. Overall, the paper advances an elementary combinatorial approach to Chowla-type questions and clarifies the spectrum of admissible densities arising from shifted convolutions of ±1-valued completely multiplicative functions.
Abstract
We study the shifted convolution sums associated to completely multiplicative functions taking values in $\{\pm 1\}$ and give combinatorical proofs of two recent results in the direction of Chowla's conjecture. We also determine the corresponding "spectrum".
