Definition:Yoneda Functor

Definition
Let $C$ be a locally small category.

Let $C^{\operatorname{op}}$ be its opposite category.

Let $\mathbf{Set}$ be the category of sets.

Let $\left[{C^{\operatorname{op}}, \mathbf{Set} }\right]$ be the functor category between them.

Also see

 * Yoneda Lemma
 * Definition:Hom Functor