Definition:Mapping/Class Theory

Definition
Let $V$ be a basic universe.

A mapping $f$ in the context of class theory is a relation such that:


 * $f \subseteq V \times V$:


 * $\forall x \in \Dom f: \exists! y \in \Img f: \tuple {x, y} \in f$

That is, for every $x$ in the domain of $f$, there exists exactly one $y$ in the image of $f$ such that $\tuple {x, y} \in f$.