The question of conditional inference, i.e., which sentences the form ``if A then, normally, B'' should follow from a set KB such sentences, has been one classic questions AI, with several well-known solutions proposed. Perhaps most notable is rational closure construction Lehmann and Magidor, under inferred conditionals forms consequence relation, satisfies all rules preferential reasoning, *p...

In general, computing answers to queries in disjunctive deductive databases is CoNP-complete and therefore computationally infeasible. However, there are some tractable classes of disjunctive databases. In this paper, we present polynomial time algorithms to compute answers to queries in one such tractable class of disjunctive databases where at most two atoms are allowed in any disjunction.