Abstract
Recently, the logics of minimal knowledge and negation as failure MKNF [12] was used to introduce hybrid MKNF knowledge bases [14], a powerful formalism for combining open and closed world reasoning for the Semantic Web. We present an extension based on a new three-valued framework including an alternating fixpoint, the well-founded MKNF model. This approach, the well-founded MKNF semantics, derives its name from the very close relation to the corresponding semantics known from logic programming. We show that the well-founded MKNF model is the least model among all (three-valued) MKNF models, thus soundly approximating also the two-valued MKNF models from [14]. Furthermore, its computation yields better complexity results (up to polynomial) than the original semantics where models usually have to be guessed.

URL:
http://rewerse.net/publications/rewerse-publications.html#REWERSE-RP-2007-087

BibTeX:

@inproceedings{REWERSE-RP-2007-087,
	author = {Matthias Knorr and Jos\'{e} J\'{u}lio Alferes and Pascal Hitzler},
	title = {Towards Tractable Local Closed World Reasoning for the Semantic Web},
	booktitle = {Proceedings of 13th Portuguese Conference on Artificial Intelligence, Guimarães, Portugal (3rd--7th December 2007)},
	year = {2007},
	volume = {4874},
	series = {LNAI},
	pages = {3--14},
	url = {http://rewerse.net/publications/rewerse-publications.html#REWERSE-RP-2007-087}
}