A short proof of Erdős' conjecture for triple systems.

Erdős [1] conjectured that for all $${k \geq 2}$$ , $${s \geq 1}$$ and $${n \geq {k(s+1)}}$$ , an n-vertex k-uniform hypergraph $${\mathcal{F}}$$ with $${\nu(\mathcal{F})=s}$$ cannot have more than $${\max\{\binom{sk+k-1}k,\binom nk-\binom{n-s}k\}}$$ edges. It took almost fifty years to prove it for triple systems. In [5] we proved the conjecture for all s and all $${n \geq 4(s+1)}$$ . Then Łuczak and Mieczkowska [6] proved the conjecture for sufficiently large s and all n. Soon after, Frankl proved it for all s. Here we present a simpler version of that proof which yields Erdős' conjecture for $${s \geq 33}$$ . Our motivation is to lay down foundations for a possible proof in the much harder case k = 4, at least for large s. [ABSTRACT FROM AUTHOR]