Szalas, Andrzej 2013 (English)In: Logic journal of the IGPL (Print), ISSN 1367-0751, E-ISSN 1368-9894, Vol. 21, no 3, 515-535Article in journal (Refereed) Published
The current article is devoted to extensions of the rule query language 4QL proposed by Małuszyński and Szałas. 4QL is a Datalog¬¬-like language, allowing one to use rules with negation in heads and bodies of rules. It is based on a simple and intuitive semantics and provides uniform tools for lightweight versions of well-known forms of non-monotonic reasoning. In addition, 4QL is tractable w.r.t. data complexity and captures PTime queries. In the current article we relax most of restrictions of 4QL, obtaining a powerful but still tractable query language 4QL+. In its development we mainly focused on its pragmatic aspects: simplicity, tractability and generality. In the article we discuss our approach and choices made, define a new, more general semantics and investigate properties of 4QL+.
Rule language; Datalog; Datalog(is not an element of is not an element of); non-monotonic reasoning; paraconsistent semantics; agent systems
National CategoryEngineering and Technology
Identifiersurn:nbn:se:liu:diva-96481 (URN)10.1093/jigpal/jzs051 (DOI)000319472800011 (ISI)oai:DiVA.org:liu-96481 (OAI)diva2:642893 (DiVA)