$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
3.84
\begin{equation} \begin{gathered}\label{equation:Serre-fibration-HELP} \xymatrix@R =50pt@C=50pt{ ( [0,1] \times |A| ) \coprod _{ (\{ 0\} \times |A|) } ( \{ 0\} \times |B|) \ar [r] \ar@ {^{(}->}[d] & X \ar [d]^{q} \\ \empty [0,1] \times | B | \ar [r] \ar@ {-->}[ur] & S } \end{gathered} \end{equation}