“…In [23], we have proved that d BI (x, y) is a true distance metric because it satisfies the properties of non-negativity x)), and the triangle inequality (d(x, y) + d(y, z) ≥ d(x, z), for any BBAs x, y and z defined on 2 Θ . The choice of Wasserstein's distance in d BI definition is justified by the fact that Wasserstein's distance is a true distance metric and it fits well with our needs because we have to compute a distance between [Bel 1 (X), P l 1 (X)] and [Bel 2 (X), P l 2 (X)].…”