Top-down query processing in indefinite stratified databases

摘要

A top-down query processing method for indefinite stratified databases is presented. Our method is applicable to first-order (function free) databases in which negative atoms are allowed within the rule bodies, and databases are interpreted using the perfect model semantics. Our method is correct and complete, and employs a construction involving cyclic and deduction trees. Mild constraints are placed on the database in order to guarantee the termination of such constructions.