Definition:Mapping/Class Theory

Definition
Let $V$ be a basic universe.

Let $A \subseteq V$ and $B \subseteq V$ be classes.

In the context of class theory, a mapping from $A$ into $B$ is a relation $f \subseteq A \times B$ such that:


 * $\forall x \in A: \exists! y \in B: \tuple {x, y} \in f$