Knowledge Representation and Query in Semantic MediaWiki: A Formal Study
Jie Bao, Li Ding, James Hendler · 2009
Abstract. Semantic wikis extend conventional wikis, which allow users to collaboratively generate data, through semantic web technologies. This allows wiki-based information to be annotated with metadata for facilitating automated search, querying, propagation and inference. Semantic wikis have recently attained wide adoption and, with this, formal research on their functionality (e.g., inference and concept modeling) is starting to be conducted. In this paper, we present a formal analysis of the semantic technologies in an emerging semantic wiki framework called Semantic MediaWiki (SMW). In particular, we define a RDFlike model theoretical semantics for the SMW modeling language, and a closed world, minimal Herbrand model semantics for the SMW query language by a reduction to positive logic programs. We discover that the entailment problem in SMW is NL-complete thus is highly tractable, and query answering in SMW is P-complete in general and is in L if subqueries are disallowed. We show that such a formalization allows us to discover some rather powerful usages of SMW, such as entailment inference, and to extend SMW with some frequently needed features, like negation as failure. 1