Example 8.5.1.5. Let $\operatorname{\mathcal{C}}$ be an $\infty $-category containing an object $X$. If an object $Y \in \operatorname{\mathcal{C}}$ is isomorphic to $X$, then $Y$ is a retract of $X$. In particular, the object $X$ is a retract of itself.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$