Hypotheses Founded Semantics of Logic Programs for Information Integration in Multi-Valued Logics

We address the problem of integrating information coming from different sources. The information consists of facts that a central server collects and tries to combine using (a) a set of logical rules, i.e. a logic program, and (b) a hypothesis representing the server’s own estimates. In such a setting incomplete information from a source or contradictory information from different sources necessitate the use of many-valued logics in which programs can be evaluated and hypotheses can be tested. To carry out such activities we propose a formal framework based on bilattices such as Belnap’s four-valued logics. In A preliminary version of this paper appeared in the form of an extended abstract in the proceedings of the first International Conference on Theoretical Computer Science (IFIP TCS 2000) Exploring New Frontiers of Theoretical Informatics. Corresponding author. Istituto di Elaborazione della Informazione, Consiglio Nazionale delle Ricerche, Area della Ricerca CNR di Pisa, Via Moruzzi,1 I-56124 Pisa, Phone (39) 050 315 2901, Fax (39) 050 315 2810, [email protected] Laboratoire de Recherche en Informatique, UMR 8623, Université de Paris Sud, Bat. 490, 91405 Orsay, (33) 1 69 15 66 24, [email protected]. Part of this research work was conducted while this author was visiting with the Meme Media Laboratory, University of Hokkaido, Japan. Department of Computer Science, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK. Phone +44-20 7631 6796, Fax +44-20 7631 6727, [email protected]. Partially supported by a Marie Curie Fellowship, EC Contract No: HPMF-CT-1999-0393