\begin{definition}[Definition:Out-Degree]
Let $G = \struct {V, E}$ be a digraph.
Let $v \in V$ be a vertex of $G$.
The '''out-degree of $v$ in $G$''' is the number of arcs which are incident from $v$.
It is denoted $\map {\operatorname {outdeg}_G} v$, or just $\map {\operatorname {outdeg} } v$ if it is clear from the context which digraph is being referred to.
\end{definition}