
theorem Th9:
  for X being 1-sorted, Y being TopStruct, f being Function of X,Y
  holds the carrier of Image f = rng f
proof
  let X be 1-sorted,Y be TopStruct, f be Function of X,Y;
  thus the carrier of Image f = [#](Y|(rng f)) .= rng f by PRE_TOPC:def 5;
end;
