Kerodon

$\Newextarrow{\xRightarrow}{5,5}{0x21D2}$ $\newcommand\empty{}$
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$

Variant 4.3.6.11. Let $q: X \rightarrow S$ be a right fibration of simplicial sets. Then, for any morphism $f: K \rightarrow X$, the induced map $X_{/f} \rightarrow S_{ / (q \circ f)}$ is a right fibration. If $q$ is a left fibration, then $X_{f/} \rightarrow S_{ (q \circ f)/ }$ is a left fibration.