Ahlswede–Khachatrian theorem

Statement

In extremal set theory, the Ahlswede–Khachatrian theorem generalizes the Erdős–Ko–Rado theorem to $t$-intersecting families. Given parameters $n$, $k$ and $t$, it describes the maximum size of a $t$-intersecting family of subsets of $\{1,\dots,n\}$ of size $k$, as well as the families achieving the maximum size.