$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
5.25
\begin{equation} \begin{gathered}\label{equation:transitivity-parametrized} \xymatrix@R =50pt@C=50pt{ \operatorname{Hom}_{\operatorname{\mathcal{C}}}(D,E) \times \operatorname{Hom}_{\operatorname{\mathcal{C}}}(C,D) \times \operatorname{\mathcal{E}}_{C} \ar [r]^-{ \operatorname{id}\times F } \ar [d] & \operatorname{Hom}_{\operatorname{\mathcal{C}}}(D,E) \times \operatorname{\mathcal{E}}_{D} \ar [d]^{ G } \\ \operatorname{Hom}_{\operatorname{\mathcal{C}}}(C,E) \times \operatorname{\mathcal{E}}_{C} \ar [r]^-{ H } & \operatorname{\mathcal{E}}_{E} } \end{gathered} \end{equation}