Reasoning About Typicality in Low Complexity DLs: The Logics εL~⊥T_(min)and DL-Lite_cT_(min)

摘要

We propose a nonmonotonic extension of low complexity Description Logics εL~⊥ and DL-Lite_(core) for reasoning about typicality and defeasible properties. The resulting logics are called εL~⊥T_(min) and DL-Lite_cT_(min). Concerning DL-Lite_cT_(min) we prove that entailment is in Π_2~p. With regard to εL~⊥T_(min), we first show that entailment remains EXPTIME-hard. Next we consider the known fragment of Left Local εL~⊥T_(min) and we prove that the complexity of entailment drops to Π_2~p.