xASP: An Explanation Generation System for Answer Set Programming

Ly Ly T. Trieu, Tran Cao Son, Marcello Balduccini

Abstract: In this paper, we present a system, called xASP, for generating explanations that explain why an atom belongs to (or does not belong to) an answer set of a given program. The system can generate all possible explanations for a query without the need to simplify the program before computing explanations, i.e., it works with non-ground programs. These properties distinguish xASP from existing systems such as $$\texttt{xClingo}$$ , $$\texttt{DiscASP}$$ , $$\textit{exp}(\textit{ASP}^c)$$ , and $$\textit{s(CASP)}$$ , which also generate explanations for queries to logic programs under the answer set semantics but simplify and ground the programs (the three systems $$\texttt{xClingo}$$ , $$\texttt{DiscASP}$$ , $$\textit{exp}(\textit{ASP}^c)$$ ) or do not always generate all possible explanations (the system $$\textit{s(CASP)}$$ ). In addition, the output of xASP is insensitive to syntactic variations such as the order conditions and the order of rules, which is also different from the output of $$\textit{s(CASP)}$$ .