Description Logics for Relative Terminologies

Abstract. Context-sensitivity has been for long a subject of study in linguistics, logic and computer science. Recently the problem of reasoning with contextual knowledge has been picked up also by the Semantic Web community. In this paper we introduce a conservative extension to the Description Logic ALC which supports representation of ontologies con-taining relative terms, such as ‘big ’ or ‘tall’, whose meaning depends on the choice of a particular comparison class (context). We define the lan-guage and investigate its computational properties, including the speci-fication of a tableau-based decision procedure and complexity bounds.