Query processing in annotated logic programming: Theory and implementation

Annotated logic is a formalism that has been applied to a variety of situations in knowledge representation, expert database systems, quantitative reasoning, and hybrid databases [6], [13], [19], [20], [21], [22], [23], [24], [30], [33], [35], [36]. Annotated Logic Programming (ALP) is a subset of annotated logics that can be used directly for programming annotated logic applications [22], [23]. A top-down query processing procedure containing elements of constraint solving, called ca-resolution, is developed for ALPs. It simplifies a number of previously proposed procedures, and also improves on their efficiency. The key to its development is in observing that satisfaction, as introduced originally for ALPs, may be naturally generalized. A computer implementation of ca-resolution for ALPs is described which offers important theoretical and practical insights. Strategies for improving its efficiency are discussed.