$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.20
\begin{equation} \begin{gathered}\label{equation:relative-Kan-extension-existence4} \xymatrix@R =50pt@C=50pt{ \operatorname{\mathcal{C}}^{0}_{/C} \ar [rr] \ar [d] & & \operatorname{\mathcal{D}}\ar [d]^{U} \\ ( \operatorname{\mathcal{C}}^0_{/C})^{\triangleright } \ar [r] \ar@ {-->}[urr]^{ F_ C } & \operatorname{\mathcal{C}}\ar [r]^-{G} & \operatorname{\mathcal{E}}} \end{gathered} \end{equation}