Let $A,B,C,D\in \text{Obj}\webleft (\mathcal{C}\webright )$ and let $f\colon A\to B$ and $g\colon B\to C$ be morphisms of $\mathcal{C}$.
- Interaction Between Precomposition and Postcomposition. We have
- Interaction With Composition I. We have
- Interaction With Composition II. We have
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Interaction With Composition III. We have
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Interaction With Identities. We have
\begin{align*} \webleft (\text{id}_{A}\webright )^{*} & = \text{id}_{\textup{Hom}_{\mathcal{C}}\webleft (A,B\webright )},\\ \webleft (\text{id}_{B}\webright )_{*} & = \text{id}_{\textup{Hom}_{\mathcal{C}}\webleft (A,B\webright )}. \end{align*}