Where x = 0,
<table><tr><td>g<sub>ij</sub> =
<td><table>
<tr><td>−1<td>0<td>0<td>−1
<tr><td>0<td>1<td>0<td>0
<tr><td>0<td>0<td>1<td>0
<tr><td>−1<td>0<td>0<td>−1/2</table></table>
the eigenvalues of which are