Example 5.1.1.5. Let $q: X \rightarrow S$ be a morphism of simplicial sets which restricts to an isomorphism from $X$ to a full simplicial subset of $S$ (see Definition 4.1.2.15). Then every edge of $X$ is both $q$-cartesian and $q$-cocartesian.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$