# P. 206, lines 4 and 7

${\displaystyle {\hat {\xi }}^{1}=\left[{\begin{array}{c}{\hat {\xi }}_{1}^{1}\\{\hat {\xi }}_{2}^{1}\end{array}}\right]=\left[{\begin{array}{c}1\\-i\end{array}}\right].}$
${\displaystyle {\hat {\xi }}^{2}=\left[{\begin{array}{c}{\hat {\xi }}_{1}^{2}\\{\hat {\xi }}_{2}^{2}\end{array}}\right]=\left[{\begin{array}{c}1\\i\end{array}}\right].}$