\[\varepsilon_{1}=\frac{1}{\text{E}}\left(\sigma_{1}-v \sigma_{2}\right) \]\[\left|\sigma_{1}\right| \geq\left|\sigma_{2}\right|\]
\[\varepsilon_{2}=\frac{1}{\text{E}}\left(\sigma_{2}-v \sigma_{1}\right) \]\[\left|\sigma_{2}\right| \geq\left|\sigma_{1}\right|\]