\begin{circustimelaw}{narrow-time-budget-1}
\begin{circusaction*}
  \circwait t_1 \upto t_2 ~ \refby ~ \circwait t_1' \upto t_2' \; \provided \; t_1 \leq t_1' \; \provand \; t_2' \leq t_2
\end{circusaction*}
\end{circustimelaw}
