Prioritized Assertional-Based Removed Sets Revision of DL-Lite Belief Bases

Institute for Information Systems, VCLA and WPI hosted Odile Papini

ABSTRACT

In real world applications, information is often provided by multiple sources having different priority levels reflecting for instance their reliability. This talk presents “Prioritized Removed Sets Revision” (PRSR) for revising stratified DL-Lite knowledge bases when a new sure piece of information, called the input, is added. The strategy of revision is based on inconsistency minimization and consists in determining smallest subsets of assertions (prioritized removed sets) that should be dropped from the current stratified knowledge base in order to restore consistency and accept the input. We consider different forms of input: A membership assertion, a positive or a negative inclusion axiom. To characterize our revision approach, we first rephrase Hansson’s postulates for belief bases revision within a DL-Lite setting, we then give logical properties of PRSR operators. In some situations, the revision process leads to several possible revised knowledge bases where defining a selection function is required to keep results within DL-Lite fragment. Finally we show how to use the notion of hitting set in order to compute the PRSR outcome and we give some results on the complexity of PRSR operators.

Odile Papini, Aix-Marseille Université