Update 12_band_structures_in_higher_dimensions_solutions.md - typo

src/12_band_structures_in_higher_dimensions_solutions.md

@@ -102,7 +102,7 @@ $$
 ### Subquestion 4
 Using the symmetry of the matrix, we try a few eigenvectors:
 $$
-\hat{v_\pm}=
+\mathbf{v_\pm}=
 \begin{pmatrix}
     1 \\ 
     \pm 1 \\
@@ -111,7 +111,7 @@ $$
 \end{pmatrix}
 $$
 $$
-\hat{v_\alpha}=
+\mathbf{v_\alpha}=
 \begin{pmatrix}
     \alpha \\ 
     1 \\