 A generalization is the spectral-decomposition modal interpretation (SDMI, Vermaas and Dieks 1995). SDMI is based on the spectral decomposition of the reduced density operator: the definite-valued properties \(\Pi_i\) of a system and their corresponding probabilities \(\mathrm{Pr}_i\) are given by the non-zero diagonal elements of the spectral decomposition of the system’s state,