$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
4.82
\begin{equation} \begin{gathered}\label{equation:testing-faithfulness-homotopy} \xymatrix@C =50pt@R=50pt{ \operatorname{\mathcal{C}}\ar [d]^{F} \ar [r] & \operatorname{N}_{\bullet }(\mathrm{h} \mathit{\operatorname{\mathcal{C}}}) \ar [d]^{ \operatorname{N}_{\bullet }( \mathrm{h} \mathit{F} ) } \\ \operatorname{\mathcal{D}}\ar [r] & \operatorname{N}_{\bullet }( \mathrm{h} \mathit{\operatorname{\mathcal{D}}} ) } \end{gathered} \end{equation}