Recall that the definition of a general open map f : X Y is that for any open set U CX, f(U) is open in Y. Are the following maps open? You may sketch your reason. f: CC, where f(z) = z. f: CR, where f(z) = |2|2. f: CR, where f(z) = Re(z) Im(z) f: CR, f(z) = Re(z +2z)