Corollary 5.43.
If \(\Sigma \subseteq \Ar(T)\) consists of monomorphisms, then \(\Sigma^c = \Sigma^m\).
Proof
If \(f\) is a monomorphism, \(\Delta_f\) is an isomorphism, hence automatically contained in \(\Sigma^m\). The class version of the ABFJ formula from Remark 5.40 therefore gives \(\Sigma^c = (\Sigma^{\Delta})^m = \Sigma^m\).