A theory of inductive query answering

We introduce the Boolean inductive query evaluation problem, which is concerned with answering inductive queries that are arbitrary Boolean expressions over monotonic and anti-monotonic predicates. Secondly, we develop a decomposition theory for inductive query evaluation in which a Boolean query Q is reformulated into k sub-queries Q/sub i/ = Q/sub A/ /spl and/ Q/sub M/ that are the conjunction of a monotonic and an anti-monotonic predicate. The solution to each subquery can be represented using a version space. We investigate how the number of version spaces k needed to answer the query can be minimized. Thirdly, for the pattern domain of strings, we show how the version spaces can be represented using a novel data structure, called the version space tree, and can be computed using a variant of the famous a priori algorithm. Finally, we present experiments that validate the approach.