$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
3.68
\begin{equation} \begin{gathered}\label{equation:connectivity-diagram} \xymatrix@R =50pt@C=50pt{ X \ar [d]^{f} \ar [r] & X' \ar [d]^{f'} \\ Y \ar [r] & Y'. } \end{gathered} \end{equation}