Remark 4.3.2.2. In the situation of Definition 4.3.2.1, we will generally abuse notation by identifying $\operatorname{\mathcal{C}}$ and $\operatorname{\mathcal{D}}$ with full subcategories of the join $\operatorname{\mathcal{C}}\star \operatorname{\mathcal{D}}$.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$