A higher order Levin-Feinleib theorem

TL;DR

This paper generalizes the Levin-Feinleib theorem to certain multiplicative functions, providing an asymptotic formula with an explicit error term using a differential equation approach.

Contribution

It extends the classical Levin-Feinleib theorem to a broader class of multiplicative functions with a new method involving differential equations.

Findings

Provides asymptotic estimates for sums of multiplicative functions

Generalizes Levin-Feinleib theorem to non-square-free functions

Uses differential equations to derive results

Abstract

When restricted to some non-negative multiplicative function, say f, bounded on primes and that vanishes on non square-free integers, our result provides us with an asymptotic for $\sum_{n \le X}f(n)/n$ with error term $O((\log X)^{\kappa-h-1+\varepsilon})$ (for any positive $\varepsilon>0$) as soon as we have $\sum_{p\le Q}f(p)(\log p)/p=\kappa\log Q+\eta+O(1/(\log2Q)^h)$ for a non-negative $\kappa$ and some non-negative integer $h$. The method generalizes the 1967-approach of Levin and Fainleib and uses a differential equation.