Proof.
Using Lurie’s combinatorial simplicial model category of \(\infty\)-preoperads [Lur17, § 2.1.4], one can define the \(\infty\)-operad \(\nabla_n\) as a fibrant resolution of the \(\infty\)-preoperad \([1] \xrightarrow{\underline{n}_+ \rightarrow\underline{1}_+} \mathrm{Fin}_*\). ◻