prefer (old) isa-index as provided here, to get exactly the same index layout as in Isabelle2012;
more accurate ROOT/files;
\index{model checking example|(}%
\index{lfp@{\texttt{lfp}}!applications of|see{CTL}}
\input{Base.tex}
\input{PDL.tex}
\input{CTL.tex}
\index{model checking example|)}