2003/12/19 by Paolo Ferraris, Ferraris, Paolo, Vladimir Lifschitz +1
Computer Science · #Artificial Intelligence (cs.AI) #F.4.1 #FOS: Computer and information sciences #I.2.3 #Logic, Reasoning, and Knowledge #Logic, programming, and type systems #Multi-Agent Systems and Negotiation #cs.AI
paper · pdf · doi:10.48550/arxiv.cs/0312045
To appear in Theory and Practice of Logic Programming
arxiv created 2003/12/19 · openalex publication_date 2003/12/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We compare two recent extensions of the answer set (stable model) semantics of logic programs. One of them, due to Lifschitz, Tang and Turner, allows the bodies and heads of rules to contain nested expressions. The other, due to Niemela and Simons, uses weight constraints. We show that there is a simple, modular translation from the language of weight constraints into the language of nested expressions that preserves the program's answer sets. Nested expressions can be eliminated from the result of this translation in favor of additional atoms. The translation makes it possible to compute answer sets for some programs with weight constraints using satisfiability solvers, and to prove the strong equivalence of programs with weight constraints using the logic of here-and there.