Description Logics Slawek Nowaczyk, LU AI seminar, April 2nd, 2003 Abstract In this seminar I would like to present Description Logics -- a logic whose expressive power lies in between propositional and predicate logics. Thus Description Logics is more expressive than zero-order logic while still retaining the decidability property. I will begin my seminar with overview of different properties of available logics, I will point out some issues related to the algorithm complexity theory and than I will present one of the simplest Description Logics.