Bourgain-Chang's proof of the weak ErdH{o}s-Szemer\'edi conjecture

This is an exposition of the following `weak' Erd\H{o}s-Szemer\'edi conjecture for integer sets proved by Bourgain and Chang in 2004. For any $\gamma > 0$ there exists $\Lambda(\gamma) > 0$ such that for an arbitrary $A \subset \mathbb{N}$, if $|AA| \leq K|A|$ then $$E_{+}(A) \leq K^{\Lambda}|A|^{2+\gamma}.$$