Tournament Kings
 Definition: In a tournament graph $T$, a vertex $v \in V(T)$ is a King if and only if for every other vertex $x \in V(T)$ there exists a directed path from $v$ to $x$ with a length of at most $2$.
 Theorem 1: In every tournament graph $T$, there exists a vertex $v \in V(T)$ that is a king