For $\overline{L}$ and $\overline{L}^{\prime}\in\widehat{\operatorname{Pic}}_{C^{0}}(X)$ such that both $L$ and $L^{\prime}$ are generated by global sections, we have the following:

1. (1)

   $\sigma_{\overline{L}}\geq 0$ on $X^{\operatorname{an}}$.

2. (2)

   $\sigma_{\overline{L}\otimes\overline{L}^{\prime}}(x)\leq\sigma_{\overline{L}}(x)+\sigma_{\overline{L}^{\prime}}(x)$ for $x\in X^{\operatorname{an}}$.

3. (3)

   If $\overline{L}\simeq\overline{L}^{\prime}$, then $\sigma_{\overline{L}}=\sigma_{\overline{L}^{\prime}}$ on $X^{\operatorname{an}}$.