Partition regularity of homogeneous quadratics: Current trends and challenges

Abstract

Suppose we partition the integers into finitely many cells. Can we always find a solution of the equation $x^2+y^2=z^2$ with $x,y,z$ on the same cell? What about more general homogeneous quadratic equations in three variables? These are basic questions in arithmetic Ramsey theory, which have recently been partially answered using ideas inspired by ergodic theory and tools such as Gowers-uniformity properties and concentration estimates of bounded multiplicative functions. The aim of this article is to provide an introduction to this exciting research area, explaining the main ideas behind the recent progress and some of the important challenges that lie ahead.

37 pages, small changes made, to appear in the Proceedings of the 9th European Congress of Mathematics