Rational Elimination of DL-Lite TBox Axioms

ABSTRACT. An essential task in managing description logic (DL) ontologies is the removal of problematic axioms. Such removal is formalised as the operation of contraction in belief change. In this paper, we investigate contraction over DL-Lite$_\R$ TBoxes so as to provide methods for eliminating problematic axioms in DL-Lite$_\R$ TBoxes. In belief change, a well known approach in defining contraction is via epistemic entrenchments which are essentially preference orderings over formulas. The approach however is not applicable in DLs as classic belief change assumes an underlying logic different from DLs. Thus we reformulate the epistemic entrenchment approach so as to make it applicable to DL-Lite$_\R$. We then provide representation theorem and a tractable algorithm for the reformulated approach.