theorem Th6:
  [0,{},{}] in SCM-Instr S
proof
  [0,{},{}] in {[0,{},{}]} by TARSKI:def 1;
  then [0,{},{}] in { [0,{},{}] }
   \/ { [I,{},<*a,b*>] where a,b is Element of SCM-Data-Loc: I in { 1,2,3,4 } }
    by XBOOLE_0:def 3;
  then [0,{},{}] in { [0,{},{}] }
   \/ { [I,{},<*a,b*>] where a,b is Element of SCM-Data-Loc: I in { 1,2,3,4 } }
   \/ the set of all  [6,<*i*>,{}] where i is Nat
    by XBOOLE_0:def 3;
  then [0,{},{}] in { [0,{},{}] }
   \/ { [I,{},<*a,b*>] where a,b is Element of SCM-Data-Loc: I in { 1,2,3,4 } }
   \/ the set of all  [6,<*i*>,{}] where i is Nat
   \/ the set of all  [7,<*i*>,<*a*>] where i is Nat, a is Element of
  SCM-Data-Loc by XBOOLE_0:def 3;
  hence thesis by XBOOLE_0:def 3;
end;
