Kerodon

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

Definition 3.3.1.1. Let $X_{\bullet }$ be a simplicial set. We will say that $X_{\bullet }$ is braced if, for every nondegenerate simplex $\sigma \in X_{n}$ of dimension $n > 0$, the faces $\{ d_ i(\sigma ) \} _{0 \leq i \leq n}$ are also nondegenerate.