Update 3_vector_spaces.md

src/3_vector_spaces.md

@@ -116,7 +116,7 @@ The main properties of **vector spaces** are the following:
 
   - **Inverse element**: for each vector $\vec{a} \in \mathcal{V}^n$ there exists another
   element of the same vector space, $-\vec{a}$, such that their addition results
-  in the null element, $\vec{a} + \lp -\vec{a}\rp = \vec{0}$.
+  in the null element, $\vec{a} + ( -\vec{a}) = \vec{0}$.
   
   This element it called the **inverse element**.