updates

content/Math4201/Math4201_L38.md

@@ -30,9 +30,9 @@ Choose $N\geq \frac{1}{\epsilon}$, then $\forall n\geq N,\frac{\overline{d}(x_n,
 
 We will use the topological space above to prove the following theorem.
 
-#### Theorem for metrizable spaces
+#### Urysohn metrization theorem
 
-If $X$ is a regular and second countable topological space, then $X$ is metrizable.
+If $X$ is a normal (regular and second countable) topological space, then $X$ is metrizable.
 
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