Kerodon

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

Example 5.2.4.6. Let $\operatorname{\mathcal{E}}$ be a simplicial set. Then the relative join $\operatorname{\mathcal{E}}\star _{\operatorname{\mathcal{E}}} \operatorname{\mathcal{E}}$ is isomorphic to $\Delta ^1 \times \operatorname{\mathcal{E}}$.