Turán number of special four cycles in triple systems

Zoltán Füredi, András Gyárfás, Attila Sali

A {\em special four-cycle } $F$ in a triple system consists of four triples {\em inducing } a $C_4$. This means that $F$ has four special vertices $v_1,v_2,v_3,v_4$ and four triple…