Abstract
We study the problem of instance level (ABox) updates for Knowledge Bases (KBs) represented in Description Logics of the DL-Lite family. DLLite is at the basis of OWL 2 QL, one of the tractable fragments of OWL 2, the recently proposed revision of the Web Ontology Language. We examine known works on updates that follow the model-based approach and discuss their drawbacks. Specifically, the fact that model-based approaches intrinsically ignore the structural properties of KBs, leads to undesired properties of updates computed according to such semantics. Hence, we propose two novel formula-based approaches, and for each of them we develop a polynomial time algorithm to compute ABox updates for the Description Logic DL-LiteFR.