Variations around the Brun-Titchmarsh Inequality by Olivier Ramare

In 1976, Balasubramanian and Ramachandra discovered a

new way to get the classical zero-free region for the Riemann zeta-
function. Their method is based on the Brun-Titchmarsh Inequality.

We shall present this way of doing and continue with a large sieve
q-analogue that is useful in the 7 cubes problem and with another
implementation of a similar idea that we require, in a joined work with
P. Srivastav and R. Balasubramanian, to investigate products of three
primes in some arithmetic progression.

[ayodeleemmanuel]

pls someone ask me what is the name and function of that fi of q