$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
11.15
\begin{equation} \begin{gathered}\label{equation:proof-of-relative-universality} \xymatrix@R =50pt@C=50pt{ \operatorname{\mathcal{E}}' \ar [d]^{U'} \ar [r]^-{ \widetilde{\mathscr {F}}' } & \operatorname{\mathcal{QC}}_{\operatorname{Obj}} \ar [d]^{V} \\ \operatorname{\mathcal{C}}' \ar [r]^-{ \mathscr {F}' } & \operatorname{\mathcal{QC}}} \end{gathered} \end{equation}