$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.56
\begin{equation} \begin{gathered}\label{equation:covariant-transport-as-Kan-extension} \xymatrix@C =50pt@R=50pt{ \operatorname{\mathcal{E}}\ar [d]^{U} \ar [r]^-{\beta } & \{ \Delta ^0 \} \operatorname{\vec{\times }}_{ \operatorname{\mathcal{S}}} \operatorname{\mathcal{S}}\ar [d] \\ \operatorname{\mathcal{C}}\ar [r]^-{ \mathscr {F} } & \operatorname{\mathcal{S}}} \end{gathered} \end{equation}