\begin{circuslaw}{extract-hide-par-left}
\begin{circusaction*}
  (A_1 \circhide cs) \lpar ns_1 | cs' | ns_2 \rpar A_2 \; \equiv \; (A_1 \lpar ns_1 | cs' | ns_2 \rpar A_2) \circhide cs
  \also
  \provided \; cs \cap cs' = \emptyset \; \provand \; cs \cap \usedC(A_2) = \emptyset
\end{circusaction*}
\end{circuslaw}
