On the existence of stable models of non-stratified logic programs

In this paper we analyze the relationship between cyclic definitions and consistency in GelfondLifschitz's answer sets semantics (initially defined as `stable model semantics'). This paper introduces a fundamental result, which is very relevant for Answer Set programming, and planning. For the first time since the definition of the stable model semantics, the class of logic programs for which a stable model exists is given a syntactic characterization. This condition may have a practical importance both for defining new algorithms for checking consistency and computing answer sets, and for improving the existing systems. The approach of this paper is to introduce a new canonical form (to which any logic program can be reduced to), to focus the attention on cyclic dependencies. The technical result is then given in terms of programs in canonical form (canonical programs), without loss of generality: the stable models of any general logic program coincide (up to the language) ...

• Type: Journal
• Year: 2004
• Where: CORR
• Authors: Stefania Costantini
• Keywords: CORR 2004, Education, Logic Program, Stable Model Semantics, Stable Models