Kerodon

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

Example 3.1.3.12. Let $q: X \rightarrow S$ be a morphism of simplicial sets. Then, for each vertex $s \in S$, the simplicial set $\operatorname{Fun}_{/S}( \{ s\} , X)$ can be identified with the fiber $X_{s} = \{ s\} \times _{S} X$.