$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.45
\begin{equation} \begin{gathered}\label{equation:all-relative-colimits} \xymatrix@R =50pt@C=50pt{ K \ar [r]^-{f} \ar [d] & \operatorname{\mathcal{C}}\ar [d]^{U} \\ K^{\triangleright } \ar [r] \ar@ {-->}[ur]^{ \overline{f} } & \operatorname{\mathcal{D}}} \end{gathered} \end{equation}