Generalized Quanti ers

We considered the problem of processing queries that contain generalized quanti ers. We demonstrate that current relational systems are ill-equipped, both at the language and at the query processing level, to deal with such queries. We propose a boolean matrix approach which establishes the feasibility of building systems that can process queries with generalized quanti ers e ciently, and we provide insights into the intrinsic di culties associated with processing such queries.