Classi quasi additive di eventi e coerenza di probabilità condizionate

By using the C_0-coherence concept, we prove that, given a finitely additive conditional probability P on E x H, with E an algebra of events, if the class H of the conditioning events is P-almost additive then P is a coherent conditional probability. Moreover, the extension of P on E x H*, with H contained in H*, such that the class H* of the conditioning events is additive, is examined. Finally, some examples of P-almost additive classes are shown and a sufficient condition of almost additivity is given.