Kerodon

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

Example 4.1.5.3. Let $X$ be a simplicial set. Then the projection map $f: X \rightarrow \Delta ^0$ is an inner covering map if and only if $X$ is isomorphic to the nerve of a category (this is a restatement of Proposition 1.2.3.1).