$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
10.17
\begin{equation} \begin{gathered}\label{equation:comparison-map-with-decalage} \xymatrix@C =50pt@R=50pt{ & C \circ \iota \circ C \ar [dr]^{ \operatorname{id}_ C \circ \epsilon } & \\ C \ar [ur]^{ \eta \circ \operatorname{id}_{C} } \ar [rr]^{ \operatorname{id}_{C} } & & C } \end{gathered} \end{equation}