A sharp 5/8 bound for an Erdős-Sós pairwise-sums problem

Ricky Cipollini

Let $f_3(N)$ be the least integer such that every set $A\subseteq \{1,\dots ,N\}$ of size at least $f_3(N)$ contains distinct elements $a,b,c\in A$ such that $a+b\in A$, $a+c\in A$,…