theorem
  for I being keeping_0 parahalting really-closed Program of SCM+FSA,
      J being parahalting really-closed Program of SCM+FSA
  holds IExec(I ";" J,P,s).a = IExec(J,P,IExec(I,P,s)).a
proof
  let I be keeping_0 parahalting really-closed Program of SCM+FSA,
      J be parahalting really-closed Program  of SCM+FSA;
A1: not a in dom Start-At (IC IExec(J,P,IExec(I,P,s)) + card I,SCM+FSA)
 by SCMFSA_2:102;
  IExec(I ";" J,P,s) = IncIC(IExec(J,P,IExec(I,P,s)),card I) by SCMFSA6B:20;
  hence thesis by A1,FUNCT_4:11;
end;
