A logic based approach for restoring consistency in P2P deductive databases

Abstract

This paper stems from the work in [10] in which the declarative semantics of a P2P system is defined in terms of minimal weak models. Under this semantics each peer uses its mapping rules to import minimal sets of mapping atoms allowing to satisfy its local integrity constraints. This behavior results to be useful in real world P2P systems in which peers often use the available import mechanisms to extract knowledge from the rest of the system only if this knowledge is strictly needed to repair an inconsistent local database. Then, an inconsistent peer, in the interaction with different peers, just imports the information allowing to restore consistency, that is minimal sets of atoms allowing the peer to enrich its knowledge so that restoring inconsistency anomalies. The paper extends previous work by proposing a rewriting technique that allows modeling a P2P system, PS, as a unique logic program whose minimal models correspond to the minimal weak models of PS.