Facilitating DL-based hybrid reasoning with inference fusion
abstract. Description Logics stem from Semantic Networks and Frames. They deal with the representation of structured concepts, and reasoning with them. The structure of a concept is described using a language, called concept language, comprising boolean operators (conjunction, disjunction, negation) and various forms of quantiica-tion over the attributes (or, roles) of the given concept. A noticeable diierence with other structuring formalisms is that also roles can be given some internal structure, e.g. a role can be expressed as a conjunction of two other roles. We survey techniques for reasoning, and computational complexity of reasoning problems in Description Logics, referring to four diierent settings: 1) reasoning with plain concept expressions; 2) reasoning with instances of concepts; 3) reasoning with axioms expressing properties of concepts; 4) reasoning with both instances of concepts and axioms. In the end of the paper, we mention important aspects of Description Logics not dealt within this survey.