\begin{equation*} \begin{CD} E[x]/\langle p(x) \rangle @>\psi>> F[x]/\langle q(x) \rangle \\ @VV{\sigma}V @VV{\tau}V\\ E(\alpha) @>\overline{\phi}>> F(\beta) \\ @VVV @VVV\\ E @>\phi>> F \end{CD} \end{equation*}