Notation 1.1.1.1. Let $\operatorname{{\bf \Delta }}_{\operatorname{inj}}$ denote the category whose objects are linearly ordered sets of the form $[n] = \{ 0 < 1 < \cdots < n \} $ (where $n$ is a nonnegative integer) and whose morphisms are strictly increasing functions $\alpha : [m] \hookrightarrow [n]$.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$