ScalingStacks

Definition 2.3.3. Given a pointed $\infty$-operad $\mathcal{O}_{X}$, we define its underlying symmetric sequence to be

$$p\colon\mathbf{Triv}_{\operatorname{\scriptsize{act}}}^{\otimes}\times_{\mathcal{O}_{\operatorname{\scriptsize{act}}}^{\otimes}}\left(\mathcal{O}_{\operatorname{\scriptsize{act}}}^{\otimes}\right)_{/X}\to\mathbf{Triv}_{\operatorname{\scriptsize{act}}}^{\otimes}\simeq\mathbf{Fin}^{\simeq}$$

and denote it by $\mathcal{O}_{X,\mathbf{SSeq}}$. By analogy with $\infty$-operads, we denote by $\mathcal{O}_{X,\mathbf{SSeq}}^{\otimes}$ the source of $p$.