$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
3.74
\begin{equation} \begin{gathered}\label{equation:fibration-to-strong-coskeleton} \xymatrix@R =50pt@C=50pt{ \Lambda ^{m}_{i} \ar [r]^-{ \sigma _0 } \ar [d] & X \ar [d]^{u} \\ \Delta ^{m} \ar@ {-->}[ur]^{\sigma } \ar [r]^-{ \overline{\sigma } } & \operatorname{cosk}^{\circ }_{n}(X) } \end{gathered} \end{equation}