theorem
  for i being keeping_0 sequential Instruction of SCM+FSA, j being
sequential Instruction of SCM+FSA holds IExec(i ";" j,P,s).f = Exec(j, Exec(i,
  Initialized s)).f
proof
  let i be keeping_0 sequential Instruction of SCM+FSA,
      j be sequential
  Instruction of SCM+FSA;
  set Mi = Macro i;
  thus IExec(i ";" j,P,s).f = IExec(Mi ";" j,P,s).f
    .= Exec(j,IExec(Mi,P,s)).f by Th6
    .= Exec(j, Exec(i, Initialized s)).f by Th4;
end;
