$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.16
\begin{equation} \begin{gathered}\label{equation:diagram-of-Res} \xymatrix@R =50pt@C=50pt{ \operatorname{Fun}( \overline{\operatorname{\mathcal{K}}}/\operatorname{\mathcal{C}}, \operatorname{\mathcal{D}}) \ar [rr] \ar [dd]^{U \circ } \ar [dr]^{T} & & \operatorname{Fun}( \operatorname{\mathcal{K}}/\operatorname{\mathcal{C}}, \operatorname{\mathcal{D}}) \ar [dd]^{U \circ } \ar [dl] \\ & \operatorname{\mathcal{C}}& \\ \operatorname{Fun}( \overline{\operatorname{\mathcal{K}}}/\operatorname{\mathcal{C}}, \operatorname{\mathcal{E}}) \ar [rr] \ar [ur] & & \operatorname{Fun}( \operatorname{\mathcal{K}}/\operatorname{\mathcal{C}}, \operatorname{\mathcal{E}}), \ar [ul] } \end{gathered} \end{equation}