\begin{definition}[Definition:Saturation (Equivalence Relation)/Definition 3]
Let $\sim$ be an equivalence relation on a set $S$.
Let $T\subset S$ be a subset.
The '''saturation of $T$''' is the preimage of its image under the quotient mapping:
:$\overline T = q^{-1} \sqbrk {q \sqbrk T}$
Category:Definitions/Equivalence Relations
\end{definition}