On primitive Dirichlet characters and the Riemann hypothesis

Banks, William D.; Guloglu, Ahmet M.; Nevans, C. Wesley

On primitive Dirichlet characters and the Riemann hypothesis

Authors

Banks, William D.

Guloglu, Ahmet M.

Nevans, C. Wesley

Description

For any natural number $n$, let $X'_n$ be the set of primitive Dirichlet characters modulo $n$. We show that if the Riemann hypothesis is true, then the inequality $|X'_{2n_k}|\le C_2 e^{-γ} ϕ(2n_k)/\log\log(2n_k)$ holds for all $k\ge 1$, where $n_k$ is the product of the first $k$ primes, $γ$ is the Euler-Mascheroni constant, $C_2$ is the twin prime constant, and $ϕ(n)$ is the Euler function. On the other hand, if the Riemann hypothesis is false, then there are infinitely many $k$ for which the same inequality holds and infinitely many $k$ for which it fails to hold.
7 pages