Applications of additive combinatorics to rational points.
Abstract
Spectacular results in additive combinatorics provide a powerful tool
to prove existence and density statements for rational points on certain
algebraic varieties over Q. I will give a survey of recent work by
Browning, Matthiesen, the speaker, and a subsequent work by Harpaz and
Wittenberg leading to a result about families of rationally connected
varieties parameterised by the projective line: if the Brauer-Manin
obstruction controls rational points in the smooth fibres, then it
controls rational points on the total space.