$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
4.88
\begin{equation} \begin{gathered}\label{equation:relative-homotopy-other-fibrations} \xymatrix@C =50pt@R=50pt{ \Lambda ^{m}_{i} \ar [r]^-{\sigma _0} \ar [d] & \mathrm{h}_{\mathit{\leq n}}\mathit{(\operatorname{\mathcal{C}}/\operatorname{\mathcal{D}})} \ar [d]^{G} \\ \Delta ^{m} \ar@ {-->}[ur]^{\sigma } \ar [r]^-{ \overline{\sigma } } & \operatorname{\mathcal{D}}} \end{gathered} \end{equation}