Explaining inconsistency in answer set programs and extensions. (English) Zbl 1491.68047

Balduccini, Marcello (ed.) et al., Logic programming and nonmonotonic reasoning. 14th international conference, LPNMR 2017, Espoo, Finland, July 3–6, 2017. Proceedings. Cham: Springer. Lect. Notes Comput. Sci. 10377, 176-190 (2017).
Summary: Answer set programming (ASP) is a well-known problem solving approach based on nonmonotonic logic programs. hex-programs extend ASP with external atoms for accessing arbitrary external information. In this paper we study inconsistent ASP- and hex-programs, i.e., programs which do not possess answer sets, and introduce a novel notion of inconsistency reasons for characterizing their inconsistency depending on the input facts. This problem is mainly motivated by upcoming applications for optimizations of the evaluation algorithms for hex-programs. Further applications can be found in ASP debugging. We then analyze the complexity of reasoning problems related to the computation of such inconsistency reasons. Finally, we present a meta-programming encoding in disjunctive ASP which computes inconsistency reasons for given normal logic programs, and a basic procedural algorithm for computing inconsistency reasons for general hex-programs.
For the entire collection see [Zbl 1367.68005].


68N17 Logic programming
68T27 Logic in artificial intelligence
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