Title: The distribution of quadratic non-residues: A stroll through the garden
Abstract: We shall have a stroll through the garden of classical results about the distribution quadratic (non-)residues modulo a prime with an emphasis on the methods involved.
We shall also stress the depressing state of the affairs pertaining to the distribution of quadratic non-residues in non-initial segments, highlighting work by Konyagin and Shaprlinski from 2015 which surmounts some — yet far from all — of the obstacles involved.