“…Note that by construction, the function g(s 1 ) defined in (30b) expresses effective information Φ eff from (3) for the hypothetic bipartition characterized by s A = s B = √ s 1 , which may or may not exist in the actual particular system. If such "symmetric" bipartition exists, then the value s A = √ s 1 belongs to the set {s A } in (27), which implies that (29) (same as (30)) is equivalent not only to (28), but also to the necessary and sufficient condition (27). Otherwise, (28) (equivalently, (29) or (30)), formally being only sufficient, still may produce a good estimate of the necessary and sufficient condition in cases when {s A } contains values which are close to √ s 1 (corresponding to nearly symmetric partitions, if such exist).…”