Kerodon

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

Remark 1.2.1.3. Let $S_{}$ be a simplicial set. Then the collection of all summands of $S_{}$ is closed under the formation of unions and intersections (this follows immediately from the criterion of Remark 1.2.1.2).