\begin{circuslaw}{compact-write-sets-par}
\begin{circusaction*}
  A_1 \lpar ns_1 | cs | ns_2 \rpar A_2 ~ \equiv ~ A_1 \lpar ns_1' | cs | ns_2' \rpar A_2
  \also
  \provided \; (ns_1 \setdiff ns_1') \cap \wrt(A_1) = \emptyset ~ \provand ~ (ns_2 \setdiff ns_2') \cap \wrt(A_2) = \emptyset
\end{circusaction*}
\end{circuslaw}
