theorem Th5:
  [1,{},<*d1*>] in SCMPDS-Instr
proof
  [1,{},<*d1*>] in S2;
  then [1,{},<*d1*>] in {[0,{},{}]} \/ S1 \/ S2 by XBOOLE_0:def 3;
  then [1,{},<*d1*>] in {[0,{},{}]} \/ S1 \/ S2 \/ S3 by XBOOLE_0:def 3;
  then [1,{},<*d1*>] in {[0,{},{}]} \/ S1 \/ S2 \/ S3 \/ S4 by XBOOLE_0:def 3;
  hence thesis by XBOOLE_0:def 3;
end;
