$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
7.70
\begin{equation} \begin{gathered}\label{equation:bad-inverse-limit} \xymatrix@C =50pt@R=50pt{ \cdots \ar [r] & B_{\bullet }( p^{3} \operatorname{\mathbf{Z}}) \ar [r] & B_{\bullet }( p^2 \operatorname{\mathbf{Z}}) \ar [r] & B_{\bullet }( p \operatorname{\mathbf{Z}}) \ar [r] & B_{\bullet }(\operatorname{\mathbf{Z}}). } \end{gathered} \end{equation}