We want to understand when a given TBox T in a description logic L can be rewritten into a TBox T′ in a weaker description logic L′. Two notions of rewritability are considered: model-conservative rewritability (T′ entails T and all models of T can be expanded to models of T′) and L-conservative rewritability (T′ entails T and every L-consequence of T′ in the signature of T is a consequence of T ) and investigate rewritability of TBoxes in ALCI to ALC, ALCQ to ALC, ALC to EL⊥, and ALCI to DL-Litehorn. We compare conservative rewritability with equivalent rewritability, give model-theoretic characterizations of conservative rewritability, prove complexity results for deciding rewritability, and provide some rewriting algorithms.
['Boris Konev', 'Carsten Lutz', 'Frank Wolter', 'Michael Zakharyaschev']
Conservative Rewritability of Description Logic TBoxes: First Results