On Computing World Views of Epistemic Logic Programs

Abstract

This paper presents a novel algorithm for computing world views of different semantics of epistemic logic programs (ELP) and two of its realization, called Ep-asp (for an older semantics) and Ep-asp^{se} (for the newest semantics), whose implementation builds on the theoretical advancement in the study of ELPs and takes advantage of the multi-shot computation paradigm of the answer set solver Clingo. The new algorithm differs from the majority of earlier algorithms in its strategy. Specifically, it computes one world view at a time and utilizes properties of world views to reduce its search space. It starts by computing an answer set and then determines whether or not a world view containing this answer set exists. In addition, it allows for the computation to focus on world views satisfying certain properties. The paper includes an experimental analysis of the performance of the two solvers comparing against a recently developed solver. It also contains an analysis of their performance in goal directed computing against a logic programming based conformant planning system, dlv-k. It concludes with some final remarks and discussion on the future work.