
theorem Th8:
  for X being set, F being SetSequence of X holds lim_sup F c= Union F
proof
  let X be set, F be SetSequence of X;
  let x be object;
  assume x in lim_sup F;
  then ex k being Nat st x in F.(0 qua Nat+k) by Th5;
  hence thesis by PROB_1:12;
end;
