Abstract
This paper investigates the possibility of exploiting formal analysis tools developed in the database field for the purpose of studying the expressive power of description logics augmented with rule-based query languages. We report a preliminary analysis on the expressive power of such hybrid languages. Two specific languages coupling a terminological component with Horn rules are considered. It is shown that: (1) the former language defines all database collections expressed by skolemized universally quantified second order formulae where quantified predicates are monadic, and (2) the latter language defines all database collections expressed by skolemized universally quantified second order formulae where quantified predicates are dyadic or monadic.
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