Sunflowers Fa sunflower of size r with center C: IF=r S,T∈F,S∩T=C a sunflower of size 6 with core CS6 S5 4 S S3 S2 S1 Sunflowers a sunflower of size 6 with core C F a sunflower of size r with center C: |F| = r ⇥S, T ￾ F, S ⌅ T = C C