Example 5.0.0.5. Let $\operatorname{Mod}(\operatorname{ Ab })$ be the category described in Example 5.0.0.2. Then the forgetful functor $U: \operatorname{Mod}(\operatorname{ Ab }) \rightarrow \operatorname{CAlg}(\operatorname{ Ab })$ is both a cartesian fibration and a cocartesian fibration.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$