theorem Th4:
  f1 is-Evaluation-for Kai & f2 is-Evaluation-for Kai implies f1 = f2
proof
  assume that
A1: f1 is-Evaluation-for Kai and
A2: f2 is-Evaluation-for Kai;
  for H being object st H in CTL_WFF holds f1.H=f2.H
  proof
    let H be object;
    assume H in CTL_WFF;
    then reconsider H as CTL-formula by Th1;
    set n=len(H);
A3: f2 is-PreEvaluation-for n, Kai by A2;
    f1 is-PreEvaluation-for n, Kai by A1;
    hence thesis by A3,Lm26;
  end;
  hence thesis by FUNCT_2:12;
end;
