Abstract
The Semantic Web aims at extending the current Web by standards and technologies that help machines to understand the information on the Web so that they can support richer discovery, data integration, navigation, and automation of tasks. Its development proceeds in layers, and the Ontology layer is the highest one that has currently reached a sufficient maturity, in the form of the Web Ontology Language (OWL), which is based on Description Logics. Current efforts are focused on realizing the Rules layer, which should complement the Ontology layer and offer sophisticated representation and reasoning capabilities. This raises, in particular, the issue of interlinking rules and ontologies. Answer Set Programming (ASP), also called A-Prolog, is a well-known declarative programming paradigm which has its roots in Logic Programming and Non-monotonic Reasoning. Thanks to its many extensions, ASP is well-suited for modeling and solving problems which involve common sense reasoning, and has been fruitfully applied to a range of applications including data integration, configuration, diagnosis, text mining, and reasoning about actions and change. Within the context of the Semantic Web, the usage of ASP and related formalisms has been explored in different directions. They have been exploited as a tool to encode reasoning tasks in Description Logics, but also as a basis for giving a semantics to a combination of rules and ontologies. In that, increasing levels of integration have been considered: loose couplings, where rule and ontology predicates are separated, and the interaction is via a safe semantic interface like an inference relation; tight couplings, where rule and ontology predicates are separated, and the interaction is at the level of models; full integration, where no distinction between rule and ontology predicates is made. We will first briefly review ASP and ontology formalisms. We then will recall some of the issues that come up with the integration of rules and ontologies. After that, we will consider approaches to combine rules and ontologies under ASP, where particular attention well be devoted to non-monotonic description logic programs and their derivatives as a representative of loose couplings. However, also other approaches will be discussed. We further discuss the potential of such combinations, some applications, and finally some open issues. The tutorial is based on material and results obtained in joint work with Jos de Bruijn (Free University of Bolzano), Giovambattista Ianni (Universita della Calabria), Thomas Krennwallner (TU Wien), Thomas Lukasiewicz (Universita di Roma ``La Sapienza'', Axel Polleres (DERI Galway), Roman Schindlauer (TU Wien), and Hans Tompits (TU Wien).

URL:
http://rewerse.net/publications/rewerse-publications.html#REWERSE-RP-2007-141

BibTeX:

@inproceedings{REWERSE-RP-2007-141,
	author = {Thomas Eiter},
	title = {Answer Set Programming for the Semantic Web (Tutorial)},
	booktitle = {Proceedings of 23rd International Conference on Logic Programming, Porto, Portugal (8th--13th September 2007)},
	year = {2007},
	volume = {4670},
	organization = {ALP},
	series = {LNCS},
	pages = {23--26},
	url = {http://rewerse.net/publications/rewerse-publications.html#REWERSE-RP-2007-141}
}