Bombieri-Vinogradov for multiplicative functions, and beyond the $x^{1/2}$-barrier

TL;DR

This paper advances the understanding of the distribution of multiplicative functions in arithmetic progressions, extending the Bombieri-Vinogradov theorem beyond the traditional $x^{1/2}$-barrier, with new theoretical insights and limitations.

Contribution

It develops a general framework for the distribution of multiplicative functions in arithmetic progressions, surpassing the classical $x^{1/2}$-barrier, and identifies key limitations of current methods.

Findings

Extended averages to moduli up to $x^{20/39- ext{delta}}$

Identified reasons for the difficulty in generalizing Bombieri-Vinogradov

Developed new techniques for studying multiplicative functions in progressions

Abstract

Part-and-parcel of the study of "multiplicative number theory" is the study of the distribution of multiplicative functions in arithmetic progressions. Although appropriate analogies to the Bombieri-Vingradov Theorem have been proved for particular examples of multiplicative functions, there has not previously been headway on a general theory; seemingly none of the different proofs of the Bombieri-Vingradov Theorem for primes adapt well to this situation. In this article we find out why such a result has been so elusive, and discover what can be proved along these lines and develop some limitations. For a fixed residue class $a$ we extend such averages out to moduli $\leq x^{\frac {20}{39}-\delta}$.