If $\Psi|_{\sigma}=0$ then the divisor $D_{\psi}$ and the horizontal orbit ${\mathcal{V}}(\sigma)$ intersect properly. Moreover, the set $\{(m_{{\overline{\Lambda}}},l_{{\overline{\Lambda}}})\}_{{\overline{\Lambda}}\in\Pi(\sigma)}$ is a set of defining vectors of $\psi(\sigma)$ and the restriction of $D_{\psi}$ to ${\mathcal{V}}(\sigma)$ is $D_{\psi(\sigma)}$.