$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
8.5
\begin{equation} \begin{gathered}\label{equation:coslice-inclusion-equivalence} \xymatrix@R =50pt@C=50pt{ X(K) \ar [r]^-{\theta _ K} & Y(K) \ar [d] \\ X(K_0) \ar [r]^-{ \theta _{K_0} } & Y(K_0 ), } \end{gathered} \end{equation}