Alexander Borgida

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We argue that accessing the transitive closure of relationships is an important component of both databases and knowledge representation systems in Artificial Intelligence. The demands for efficient access and management of large relationships motivate the need for explicitly storing the transitive closure in a compressed and local way, while allowing(More)
We describe Telos, a language intended to support the development of information systems. The design principles for the language are based on the premise that information system development is knowledge intensive and that the primary responsibility of any language intended for the task is to be able to formally represent the relevent knowledge. Accordingly,(More)
CLASSIC is a data model that encourages the description of objects not only in terms of their relations to other known objects, but in terms of a level of intensional structure as well. The CLASSIC language of <italic>structured descriptions</italic> permits i) partial descriptions of individuals, under an 'open world' assumption, ii) answers to queries(More)
classic is a recently-developed knowledge representation system that follows the paradigm originally set out in the kl-one system: it concentrates on the de nition of structured concepts, their organization into taxonomies, the creation and manipulation of individual instances of such concepts, and the key inferences of subsumption and classi cation. Rather(More)
It is natural to view concept and role definitions in Description Logics as expressing monadic and dyadic predicates in Predicate Calculus. We show that the descriptions built using the constructors usually considered in the DL literature are characterized exactly as the predicates definable by formulas in L̈3, the subset of First Order Predicate Calculus(More)
This paper analyzes the correctness of the subsumption algorithm used in classic, a description logic-based knowledge representation system that is being used in practical applications. In order to deal e ciently with individuals in classic descriptions, the developers have had to use an algorithm that is incomplete with respect to the standard,(More)
Description logics and reasoners, which are descendants of the kl-one language, have been studied in depth in Arti cial Intelligence. After a brief introduction, we survey in this paper their application to the problems of information management, using the framework of an abstract information server equipped with several operations | each involving one or(More)
This report has been submitted forr publication outside of ITC and will probably be copyrighted if accepted for publication. It has been issued as a Technical Report forr early dissemination of its contents. In view of the transfert of copy right too the outside publisher, its distribution outside of ITC priorr to publication should be limited to peer(More)
Description logics are a popular formalism for knowledge representation and reasoning. This paper introduces a new operation for description logics: computing the “least common subsumer” of a pair of descriptions. This operation computes the largest set of commonalities between two descriptions. After arguing for the usefulness of this operation, we analyze(More)