Kerodon

\begin{equation} \begin{gathered}\label{equation:sequential-limit-as-pullback} \xymatrix@R =50pt@C=50pt{ \varprojlim _{n} \operatorname{\mathcal{C}}_ n \ar [r] \ar [d] & \operatorname{\mathcal{C}}\ar [d]^{ (\operatorname{id}, \operatorname{id}) } \\ \operatorname{\mathcal{C}}\ar [r]^-{ (\operatorname{id}, S) } & \operatorname{\mathcal{C}}\times \operatorname{\mathcal{C}}. } \end{gathered} \end{equation}