 Thus, an exclusive and exhaustive universal affirmative disjunction entails a proposition that expresses universal absence of conflict between one of the disjuncts and the contradictory of the other (“from ‘Always either every A is B or every C is D’ one can infer ‘Never either not every A is B or every C is D’ and ‘Never either not every C is D or every A is B’”, Qiyās VII.2, 380.1–4). The converse is not generally true, as the negative disjunction may be true in virtue of an impossible disjunct that is not in conflict with the other (according to the semantics of negative disjunctions discussed in Qiyās V.5). The same holds for (i-\(\mathbb{D}\)1) and (o-\(\mathbb{D}\)1) propositions.