$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.90
\begin{equation} \begin{gathered}\label{equation:isofibration-between-left} \xymatrix { A \ar [d]^{\iota } \ar [r] & \operatorname{\mathcal{E}}' \ar [d]^{\Gamma } \\ B \ar [r] \ar@ {-->}[ur] & \operatorname{\mathcal{E}}} \end{gathered} \end{equation}