The family
8c84ac627981b14b9c582" title="Click to view the MathML source">Σr consists of all
r -graphs with three edges
87d0c6b3f6e0b0033d3aa" title="Click to view the MathML source">D1,D2,D3 such that
e5c5456f1df1eae2adf784219" title="Click to view the MathML source">|D1∩D2|=r−1 and
8c" title="Click to view the MathML source">D1△D2⊆D3. A
generalized triangle ,
Tr∈Σr is an
r -graph on
ba6d" title="Click to view the MathML source">{1,2,…,2r−1} with three edges
87d0c6b3f6e0b0033d3aa" title="Click to view the MathML source">D1,D2,D3, such that
872b83741e5f8c594470b6695f1" title="Click to view the MathML source">D1={1,2,…,r−1,r},D2={1,2,…,r−1,r+1} and
D3={r,r+1,…,2r−1}.
Frankl and Füredi conjectured that for all 87e6bf" title="Click to view the MathML source">r≥4, ba" title="Click to view the MathML source">ex(n,Σr)=ex(n,Tr) for all sufficiently large n and they also proved it for 9cc6df6170e6134328e34fb63ef129da" title="Click to view the MathML source">r=3. Later, Pikhurko showed that the conjecture holds for 90069b731bec015d4f9ba8b" title="Click to view the MathML source">r=4. In this paper we determine ex(n,T5) and ex(n,T6) for sufficiently large n , proving the conjecture for 90f88" title="Click to view the MathML source">r=5,6.