Title
Efficient HEX-program evaluation based on unfounded sets
Abstract
HEX-programs extend logic programs under the answer set semantics with external computations through external atoms. As reasoning from ground Horn programs with nonmonotonic external atoms of polynomial complexity is already on the second level of the polynomial hierarchy, minimality checking of answer set candidates needs special attention. To this end, we present an approach based on unfounded sets as a generalization of related techniques for ASP programs. The unfounded set detection is expressed as a propositional SAT problem, for which we provide two different encodings and optimizations to them. We then integrate our approach into a previously developed evaluation framework for HEX-programs, which is enriched by additional learning techniques that aim at avoiding the reconstruction of the same or related unfounded sets. Furthermore, we provide a syntactic criterion that allows one to skip the minimality check in many cases. An experimental evaluation shows that the new approach significantly decreases runtime.
Year
DOI
Venue
2014
10.1613/jair.4175
J. Artif. Intell. Res. (JAIR)
Field
DocType
Volume
Polynomial hierarchy,Check-in,Sat problem,Theoretical computer science,Artificial intelligence,Polynomial complexity,Syntax,Mathematics,Machine learning,Semantics,Computation,Program evaluation
Journal
49
Issue
ISSN
Citations 
1
1076-9757
11
PageRank 
References 
Authors
0.53
49
5
Name
Order
Citations
PageRank
Thomas Eiter17238532.10
Michael Fink2114562.43
Thomas Krennwallner346829.14
Christoph Redl413713.76
Peter Schüller519222.61