Image of Set Complement

Image of Set Complement

For \(f : X \to Y\)

\[ f(A)^{c} \subseteq f(A^{c}) \quad \forall A \subseteq X \iff f \ \text{is surjective}\]

with the equality condition

\[ f(A)^{c} = f(A^{c}) \quad \forall A \subseteq X \iff f \ \text{is bijective}\]