# Kerodon

$\Newextarrow{\xRightarrow}{5,5}{0x21D2}$ $\newcommand\empty{}$

Proposition 8.1.1.11. Let $\operatorname{\mathcal{C}}$ be an $\infty$-category. Then the projection maps of Notation 8.1.1.6 determine a left fibration of simplicial sets

$(\lambda _{-}, \lambda _{+}): \operatorname{Tw}(\operatorname{\mathcal{C}}) \rightarrow \operatorname{\mathcal{C}}^{\operatorname{op}} \times \operatorname{\mathcal{C}}.$