$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
8.80
\begin{equation} \begin{gathered}\label{equation:balanced-coupling-family-over-edge1} \xymatrix@R =50pt@C=50pt{ \operatorname{\mathcal{E}}_{0} \ar [r]^-{F} \ar [d]^{ G_0 } & \operatorname{\mathcal{E}}_{1} \ar [d]^{ G_1 } \\ (\operatorname{\mathcal{E}}^{\vee }_{0})^{\operatorname{op}} \ar [r]^-{ (F^{\vee } )^{\operatorname{op}} } & ( \operatorname{\mathcal{E}}^{\vee }_{1})^{\operatorname{op}} } \end{gathered} \end{equation}