reserve x for set,
  m,n for Nat,
  a,b,c for Int_position,
  i for Instruction of SCMPDS,
  s,s1,s2 for State of SCMPDS,
  k1,k2 for Integer,
  loc,l1 for Nat,
  I,J for Program of SCMPDS,
  N for with_non-empty_elements set;
reserve P,P1,P2,Q for Instruction-Sequence of SCMPDS;

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;
