$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.59
\begin{equation} \begin{gathered}\label{equation:homotopy-pushout-as-homotopy-colimit} \xymatrix@R =50pt@C=50pt{ A \ar [r] \ar [d] & A_{0} \ar [d] \\ A_{1} \ar [r] & A_{01}, } \end{gathered} \end{equation}