\begin{definition}[Definition:Arborescence/Root]
Let $G = \left({V, A}\right)$ be a directed graph.
Let $r \in V$.
Let $G$ be an arborescence of $r$.
The vertex $r$ of $G$ is known as the '''root of (the arborescence) $G$'''.
Category:Definitions/Arborescences
\end{definition}