reserve x for set,
  m,n for Nat,
  a,b for Int_position,
  i,j,k for Instruction of SCMPDS,
  s,s1,s2 for State of SCMPDS,
  k1,k2 for Integer,
  loc,l for Nat,
  I,J,K for Program of SCMPDS;

theorem Th3:
  Shift(J,card I) c= I ';' J ';' K
proof
  set IJ= I ';' J;
  dom IJ misses dom Shift(K, card IJ) by AFINSQ_1:72;
  then
A1: IJ c= IJ ';' K by FUNCT_4:32;
  Shift(J, card I) c= IJ by FUNCT_4:25;
  hence thesis by A1,XBOOLE_1:1;
end;
