Approximate reasoning with credible subsets

The complexity of logical inference in knowledge systems grows with the system size, determined, in particular, by the number of its clauses. This growth is so rapid, that reasoning in sizeable systems becomes intractable.However, given a system S and a query Q, should we be able to detect a subset of S informative enough to provide a correct answer to Q, and small enough to fit into the range of tractable computation,the answer to Q could be produced efficiently. This paper presents a way of implementing this idea.