\begin{definition}[Definition:Range of Relation]
Let $\RR \subseteq S \times T$ be a relation, or (usually) a mapping (which is, of course, itself a relation).
The '''range''' of $\RR$, denoted  is defined as one of two things, depending on the source.
On {{ProofWiki}} it is denoted $\Rng \RR$, but this may be non-standard.
\end{definition}