$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
9.8
\begin{equation} \begin{gathered}\label{equation:pullback-of-kappa-filtered-infinity} \xymatrix@R =50pt@C=50pt{ \operatorname{\mathcal{C}}_{\pm } \ar [r]^-{E_{+}} \ar [d]^{E_{-}} & \operatorname{\mathcal{C}}_{+} \ar [d]^{ F_{+} } \\ \operatorname{\mathcal{C}}_{-} \ar [r]^-{ F_{-} } & \operatorname{\mathcal{C}}} \end{gathered} \end{equation}