Towards Tractable Local Closed World Reasoning for the Semantic Web

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.

• Type: Conference
• Year: 2007
• Where: EPIA
• Authors: Matthias Knorr, José Júlio Alferes, Pascal Hitzler
• Keywords: EPIA 2007, Mknf Models, Well-founded Mknf, Well-founded Mknf Model