Avoid a possible variable name conflict in instantiating a theorem.
Instantiating a theorem variable with new variables created a possible
variable name conflict if a record was defined with a field named
'f', 'x' etc. Using variable indices of 1 avoids the problem.
\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|)}