The category $\mathsf{Sets}$ admits a closed symmetric monoidal category with diagonals structure consisting of:
- The Underlying Category. The category $\mathsf{Sets}$ of pointed sets.
- The Monoidal Product. The product functor
\[ \times \colon \mathsf{Sets}\times \mathsf{Sets}\to \mathsf{Sets} \]
of Chapter 2: Constructions With Sets, Item 1 of Proposition 2.1.3.1.3.
- The Internal Hom. The internal Hom functor
\[ \mathsf{Sets}\colon \mathsf{Sets}^{\mathsf{op}}\times \mathsf{Sets}\to \mathsf{Sets} \]
of Chapter 2: Constructions With Sets, Item 1 of Proposition 2.3.5.1.2.
- The Monoidal Unit. The functor
\[ \mathbb {1}^{\mathsf{Sets}} \colon \mathsf{pt}\to \mathsf{Sets} \]
- The Associators. The natural isomorphism
\[ \alpha ^{\mathsf{Sets}} \colon {\times }\circ {\webleft ({\times }\times \text{id}_{\mathsf{Sets}}\webright )} \mathbin {\overset {\mathord {\sim }}{\Longrightarrow }}{\times }\circ {\webleft (\text{id}_{\mathsf{Sets}}\times {\times }\webright )}\circ {\mathbf{\alpha }^{\mathsf{Cats}}_{\mathsf{Sets},\mathsf{Sets},\mathsf{Sets}}} \]
- The Left Unitors. The natural isomorphism
\[ \lambda ^{\mathsf{Sets}}\colon {\times }\circ {\webleft (\mathbb {1}^{\mathsf{Sets}}\times \text{id}_{\mathsf{Sets}}\webright )} \mathbin {\overset {\mathord {\sim }}{\Longrightarrow }}\mathbf{\lambda }^{\mathsf{Cats}_{\mathsf{2}}}_{\mathsf{Sets}} \]
- The Right Unitors. The natural isomorphism
\[ \rho ^{\mathsf{Sets}}\colon {\times }\circ {\webleft ({\mathsf{id}}\times {\mathbb {1}^{\mathsf{Sets}}}\webright )}\mathbin {\overset {\mathord {\sim }}{\Longrightarrow }}\mathbf{\rho }^{\mathsf{Cats}_{\mathsf{2}}}_{\mathsf{Sets}} \]
- The Symmetry. The natural isomorphism
\[ \sigma ^{\mathsf{Sets}} \colon {\times } \mathbin {\overset {\mathord {\sim }}{\Longrightarrow }}{\times }\circ {\mathbf{\sigma }^{\mathsf{Cats}_{\mathsf{2}}}_{\mathsf{Sets},\mathsf{Sets}}} \]
- The Diagonals. The monoidal natural transformation
\[ \Delta \colon \text{id}_{\mathsf{Sets}}\Longrightarrow \times \circ \Delta ^{\mathsf{Cats}_{\mathsf{2}}}_{\mathsf{Sets}} \]