Remark 4.1.5.4. Let $f: X \rightarrow S$ be a morphism of simplicial sets. Then $f$ is an inner covering map if and only if the opposite morphism $f^{\operatorname{op}}: X^{\operatorname{op}} \rightarrow S^{\operatorname{op}}$ is an inner covering map.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$