ScalingStacks

Definition 2.3.1. Let $\mathbf{Fin}$ denote the skeletal version of the category of finite sets, ie the full subcategory of $\mathbf{Set}$ spanned by the objects $\left[n\right]=\left\{1,\dots,n\right\}$ for each integer $n$. We define the $\infty$-category of symmetric sequences (in spaces), denoted by $\mathbf{SSeq}$, to be $\mathcal{S}_{/\mathbf{Fin}^{\simeq}}$.