$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
8.48
\begin{equation} \begin{gathered}\label{equation:internal-hom-coupling2} \xymatrix@R =50pt@C=50pt{ \operatorname{Tw}(\operatorname{\mathcal{D}}_{+}) \ar [r]^-{ \widetilde{G} } \ar [d] & \operatorname{\mathcal{D}}\ar [d]^{\mu } \\ \operatorname{\mathcal{D}}_{+}^{\operatorname{op}} \times \operatorname{\mathcal{D}}_{+} \ar [r]^-{G^{\operatorname{op}} \times \operatorname{id}} & \operatorname{\mathcal{D}}_{-}^{\operatorname{op}} \times \operatorname{\mathcal{D}}_{+} } \end{gathered} \end{equation}