# Definition:Hom Class

## Definition

Let $\mathbf C$ be a metacategory.

Let $C$ and $D$ be objects of $\mathbf C$.

The collection of morphisms $f: C \to D$ is called a hom class and is denoted $\operatorname{Hom}_{\mathbf C} \left({C, D}\right)$.

## Also known as

If $\operatorname{Hom}_{\mathbf C} \left({C, D}\right)$ is a set, then it is also called a hom set.

Some authors hyphenate, resulting in hom-class and hom-set.

## Also denoted as

When the category $\mathbf C$ is clear, it is mostly dropped from the notation, yielding $\operatorname{Hom} \left({C, D}\right)$.

The hom class is also denoted $\mathbf C \left({C, D}\right)$, or in the case of a functor category, $\operatorname{Nat}(C, D)$.