\begin{circuslaw}{idem-par}
\begin{circusaction*}
  A \; \equiv \; (A \lpar \emptyset | \usedC(A) | \emptyset \rpar A) \; \provided \; \wrt(A) = \emptyset \; \provand \; \mbox{$A$ is deterministic}
\end{circusaction*}
\end{circuslaw}
