$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.83
\begin{equation} \begin{gathered}\label{equation:universal-colimit-preserved-by-base-change} \xymatrix { F' \ar [r]^{ \beta ' } \ar [d] & \underline{C}' \ar [d]^{ \underline{u} } \\ F \ar [r]^{\beta } & \underline{C} } \end{gathered} \end{equation}