A New Perspective on Stable Models

Paolo Ferraris, Joohyung Lee, Vladimir Lifschitz

The definition of a stable model has provided a declarative semantics for Prolog programs with negation as failure and has led to the development of answer set programming. In this paper we propose a new definition of that concept, which covers many constructs used in answer set programming (including disjunctive rules, choice rules and conditional literals) and, unlike the original definition, refers neither to grounding nor to fixpoints. Rather, it is based on a syntactic transformation, which turns a logic program into a formula of second-order logic that is similar to the formula familiar from the definition of circumscription.