“…For instance, in the same environment two very similar interactions are expected to yield similar patterns of their matrix elements (see, for example, [1,2,3]), as well to yield large overlaps of corresponding eigenstates (e.g., [4,5]) and close energy spectra (e.g., [6,7]). On the other hand, a complementary comparison that is based on the theory of spectral distributions [8,9] that invokes overall correlations of two interactions offers a broader view on their global behavior and universal properties [10,11,12,13,14].…”