
theorem Th5:
  for X being set, S being finite Subset of X, n being Element of
  NAT st n <> 0 holds support (S, n)-bag = S
proof
  let X be set, S be finite Subset of X, n be Element of NAT;
  assume n <> 0;
  then for x being object holds x in S iff (S, n)-bag.x <> 0 by Th3,Th4;
  hence thesis by PRE_POLY:def 7;
end;
