Example 1.4.0.3. Every Kan complex is an $\infty $-category. In particular, if $X$ is a topological space, then the singular simplicial set $\operatorname{Sing}_{\bullet }(X)$ is an $\infty $-category.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
Example 1.4.0.3. Every Kan complex is an $\infty $-category. In particular, if $X$ is a topological space, then the singular simplicial set $\operatorname{Sing}_{\bullet }(X)$ is an $\infty $-category.