Added measurability in separable metric spaces.

src/topology/main/interiorclosureboundary.tex

@@ -63,7 +63,7 @@
 
 \begin{definition}[Dense]
 \label{definition:dense}
-    Let $X$ be a topologicial space and $A \subset X$, then the following are equivalent:
+    Let $X$ be a topological space and $A \subset X$, then the following are equivalent:
     \begin{enumerate}
         \item $\ol{A} = X$.
         \item For every $\emptyset \ne U \subset X$ open, $A \cap U \ne \emptyset$.