Remark 8.2.1.9. By virtue of Proposition 8.2.1.7, we can restate condition $(2)$ of Proposition 8.2.1.8 as follows:
- $(2')$
Let $e$ be a morphism of $\operatorname{\mathcal{C}}$ having the property that $\lambda _{-}(e)$ is an isomorphism in the $\infty $-category $\operatorname{\mathcal{C}}_{-}^{\operatorname{op}}$. Then $F(e)$ is a $U$-cocartesian morphism of $\operatorname{\mathcal{E}}$.