theorem Th26:
  for i being shiftable Instruction of SCMPDS holds (DataPart s1 =
  DataPart s2 implies DataPart Exec(i,s1) = DataPart Exec(i,s2))
proof
  let i be shiftable Instruction of SCMPDS;
  InsCode i <> 3 by SCMPDS_4:def 10;
  hence thesis by Th25;
end;
