avoid broadcast work_available, use daisy-chained signal instead;
max_threads: allow as much as 4 * m, after extra delay;
\index{model checking example|(}%
\index{lfp@{\texttt{lfp}}!applications of|see{CTL}}
\input{CTL/document/Base.tex}
\input{CTL/document/PDL.tex}
\input{CTL/document/CTL.tex}
\index{model checking example|)}