$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.39
\begin{equation} \begin{gathered}\label{equation:relative-colimit-extension-criterion2} \xymatrix@R =50pt@C=50pt{ \operatorname{\mathcal{C}}^0 \ar [d] \ar [r]^-{F|_{\operatorname{\mathcal{C}}^{0}}} & \operatorname{\mathcal{D}}\ar [d]^{U} \\ (\operatorname{\mathcal{C}}^0)^{\triangleright } \ar [r] \ar@ {-->}[ur]^{ \overline{F}_0 } & \operatorname{\mathcal{E}}. } \end{gathered} \end{equation}