Bounded Programs: A New Decidable Class of Logic Programs with Function Symbols

While function symbols are widely acknowledged as an important feature in logic programming, they make common inference tasks undecidable. To cope with this problem, recent research has fo-cused on identifying classes of logic programs im-posing restrictions on the use of function symbols, but guaranteeing decidability of common inference tasks. This has led to several criteria, called ter-mination criteria, providing sufficient conditions for a program to have finitely many stable models, each of finite size. This paper introduces the new class of bounded programs which guarantees the aforementioned property and strictly includes the classes of programs determined by current termi-nation criteria. Different results on the correctness, the expressiveness, and the complexity of the class of bounded programs are presented.