Talks and Poster Presentations (with Proceedings-Entry):

T. Eiter, M. Fink, T. Krennwallner, C. Redl, P. Schüller:
"Exploiting Unfounded Sets for HEX-Program Evaluation";
Talk: 13th European Conference on Logics in Artificial Intelligence (JELIA 2012), Toulouse, France; 2012-09-26 - 2012-09-28; in: "13th European Conference on Logics in Artificial Intelligence (JELIA 2012)", L. del Cerro, A. Herzig, J. Mengin (ed.); Springer, LNCS 7519 (2012), ISBN: 978-3-642-33352-1; 160 - 175.

English abstract:
HEX programs extend logic programs with external computations through external atoms, whose answer sets are the minimal models of the Faber-Leone-Pfeifer-reduct. As already reasoning from Horn programs with nonmonotonic external atoms of polynomial complexity is on the second level of the polynomial hierarchy, answer set checking needs special attention; simply computing reducts and searching for smaller models does not scale well. We thus extend an approach based on unfounded sets to HEX and integrate it in a Conflict Driven Clause Learning framework for HEX program evaluation. It reduces the check to a search for unfounded sets, which is more efficiently implemented as a SAT problem. We give a basic encoding for HEX and show optimizations by additional clauses. Experiments show that the new approach significantly decreases runtime.

Answer Set Programming, Nonmonotonic Reasoning, Unfounded Sets, FLP Semantics

"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)

Related Projects:
Project Head Thomas Eiter:
Evaluierung von ASP Programming mit Externen Zugriffen

Project Head Thomas Eiter:
Modulare HEX-Programme

Project Head Thomas Eiter:
Schließen in hybriden Wissensbasen

Project Head Michael Fink:
Inconsistency Management for Knowledge-Integration Systems

Created from the Publication Database of the Vienna University of Technology.