Introduction

Abstract

Description Logics (DLs) denote a family of knowledge representation formalisms that allow to represent the terminological knowledge of an application domain in a structured and well-defined way. On the one hand, the name Description Logics emphasizes that the basic elements of these logics are concept descriptions, i.e., expressions that are built from concept names (unary predicates) and role names (binary predicates) using the concept constructors provided by the DL. On the other hand, unlike some of their predecessor formalisms, DLs are equipped with a formal logic-based semantics, which is usually defined in a model-theoretic way; for some DLs it can also be declared by translating concept descriptions into first-order formulae.