fix typos

content/Math4201/Math4201_L34.md

@@ -98,7 +98,7 @@ A $T_0$ space is regular if for any $x\in X$ and any close set $A\subseteq X$ su
 A $T_0$ space is normal if for any disjoint closed sets, $A,B\subseteq X$, there are **disjoint open sets** $U,V$ such that $A\subseteq U$ and $B\subseteq V$.
 
 <details>
-<summary></summary>
+<summary>Finer topology may not be normal</summary>
 
 Let $\mathbb{R}_K$ be the topology on $\mathbb{R}$ generated by the basis:
 
@@ -106,7 +106,7 @@ $$
 \mathcal{B}=\{(a,b)\mid a,b\in \mathbb{R},a<b\}\cup \{(a,b)-K\mid a,b\in \mathbb{R},a<b\}
 $$
 
-where $K=\coloneqq \{\frac{1}{n}\mid n\in \mathbb{N}\}$.
+where $K\coloneqq \{\frac{1}{n}\mid n\in \mathbb{N}\}$.
 
 **This is finer than the standard topology** on $\mathbb{R}$.