Normal Space is Preserved under Homeomorphism

Theorem
Let $T_A = \struct {S_A, \tau_A}$ and $T_B = \struct {S_B, \tau_B}$ be topological spaces.

Let $\phi: T_A \to T_B$ be a homeomorphism.

If $T_A$ is a normal space, then so is $T_B$.

Proof
We have that $\struct {S, \tau}$ is a normal space :


 * $\struct {S, \tau}$ is a $T_4$ space
 * $\struct {S, \tau}$ is a $T_1$ (Fréchet) space.

From $T_4$ Space is Preserved under Homeomorphism:
 * If $T_A$ is a $T_4$ space, then so is $T_B$.

From $T_1$ Space is Preserved under Homeomorphism:
 * If $T_A$ is a $T_1$ (Fréchet) space, then so is $T_B$.

Hence the result.