
theorem
  for T being non empty TopSpace holds T, the TopStruct of T are_homeomorphic
proof
  let T be non empty TopSpace;
  reconsider f = id T as Function of T, the TopStruct of T;
  take f;
  thus dom f = [#]T;
  thus rng f = [#]T
    .= [#]the TopStruct of T;
  thus f is one-to-one;
  thus f is continuous by YELLOW12:36;
  thus thesis by YELLOW12:36;
end;
