Corollary 4.2.4.11. For every integer $n \geq 0$, the inclusion map $\iota : \{ 0\} \hookrightarrow \Delta ^ n$ is left anodyne.
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
Proof of Corollary 4.2.4.11. We may assume $n > 0$ (otherwise the result is trivial). Choose an integer $0 \leq i < n$, so that the horn inclusion $\Lambda ^{n}_{i} \hookrightarrow \Delta ^{n}$ is left anodyne. It will therefore suffice to show that the inclusion $\{ 0\} \hookrightarrow \Lambda ^{n}_{i}$ is left anodyne, which follows from Proposition 4.2.4.10. $\square$