CARDINALITY RESTRICTIONS ON CONCEPTS

The concept description formalisms of existing description logics syst ems allow the user to express local cardinality restrictions on the fi llers of a particular role. It is not possible, however, to introduce global restrictions on the number of instances of a given concept. Thi s article argues that such cardinality restrictions on concepts are of importance in applications such as configuration of technical systems , an application domain of description logics systems that is currentl y gaining in interest, It shows that including such restrictions in th e description language leaves the important inference problems such as instance testing decidable. The algorithm combines and simplifies the ideas developed for the treatment of qualified number restrictions an d of general terminological axioms.