$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
5.18
\begin{equation} \begin{gathered}\label{equation:inner-fibration-silliness} \xymatrix@R =50pt@C=50pt{ \Lambda ^{n}_{i} \ar [r]^-{ \sigma _0 } \ar [d] & \Delta ^1 \times \operatorname{\mathcal{E}}\ar [d] \\ \Delta ^ n \ar@ {-->}[ur]^{\sigma } \ar [r]^-{ \overline{\sigma } } & \operatorname{\mathcal{E}}\star _{\operatorname{\mathcal{E}}'} \operatorname{\mathcal{E}}} \end{gathered} \end{equation}