Chebyshev's bias without linear independence
Mounir Hayani
TL;DR
This work addresses Chebyshev's bias in primes within residue classes using a weighted prime count $\pi_{1/2}(x;q,a)=\sum_{p\le x} p^{-1/2}$, without assuming linear independence of zeros. By employing GRH, explicit formulas, and a summation-by-parts approach, it proves that the natural and logarithmic densities for the weighted bias exist and equal 1, with a precise main term involving $\log\log x$ and a constant $C$, and a bias constant $M(q;a,b)$. In the special case $q=4$, this yields a natural density of 1 for $\pi_{1/2}(x;4,3) > \pi_{1/2}(x;4,1)$, demonstrating Chebyshev’s bias under GRH without LI or DRH. The results also establish DRH-type conclusions for almost all $x$ and provide a mean-value expression with an explicit leading term and tight error control, strengthening connections between classical prime number theorems in AP and modern bias phenomena.
Abstract
We confirm Chebyshev's observation that primes are strikingly more abundant in non-square residue classes modulo a fixed integer under the Generalized Riemann Hypothesis (GRH) by proving a (natural) density 1 statement for prime counting functions in residue classes where each prime is weighted by its inverse square root. In contrast to the majority of the existing literature on the subject, we do not need to restrict to logarithmic densities to measure Chebyshev's bias and we do not rely on any hypothesis related to L-function zeros that is stronger than GRH.
