$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
4.25
\begin{equation} \begin{gathered}\label{equation:characterize-categorical-pullback22} \xymatrix@R =50pt@C=50pt{ \operatorname{Fun}(X, \operatorname{\mathcal{C}}_{01} )^{\simeq } \ar [r] \ar [d] & \operatorname{Fun}( X, \operatorname{\mathcal{C}}_0)^{\simeq } \ar [d] \\ \operatorname{Fun}(X, \operatorname{\mathcal{C}}_1)^{\simeq } \ar [r] & \operatorname{Fun}(X, \operatorname{\mathcal{C}})^{\simeq } } \end{gathered} \end{equation}