Remark 1.1.4.5. Let $S$ be a simplicial set and let $\sigma $ be a nondegenerate $n$-simplex of $S$. Then $\sigma $ is contained in the $k$-skeleton $\operatorname{sk}_{k}(S)$ if and only if $n \leq k$ (see Proposition 1.1.2.10).
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$