Definition:Image of Relation/Also known as

Definition
The image of a relation $\RR$, when in the context of set theory, is often seen referred to as the image set of $\RR$.

Some sources refer to this as the direct image of a relation, in order to differentiate it from an inverse image.

Rather than apply a relation $\RR$ directly to a subset $A$, those sources often prefer to define the direct image mapping of $\RR$ as a separate concept in its own right.

Other sources call the image of $\RR$ its range, but this convention is discouraged because of potential confusion.

Many sources denote the image of a relation $\RR$ by $\map {\operatorname {Im} } \RR$, but this notation can be confused with the imaginary part of a complex number $\map \Im z$.

Hence on it is preferred that $\Img \RR$ be used.