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We present a novel reasoning calculus for the description logic SHOIQ + —a knowledge representation formalism with applications in areas such as the Semantic Web. Unnecessary nondeterminism and the construction of large models are two primary sources of inefficiency in the tableau-based reasoning calculi used in state-of-the-art reasoners. In order to(More)
We present a novel reasoning calculus for Description Logics (DLs)—knowledge representation formalisms with applications in areas such as the Semantic Web. In order to reduce the nondeterminism due to general inclusion axioms, we base our calculus on hypertableau and hyperresolution calculi, which we extend with a blocking condition to ensure termination.(More)
OBO is an ontology language that has often been used for modeling ontologies in the life sciences. Its definition is relatively informal , so, in this paper, we provide a clear specification for OBO syntax and semantics via a mapping to OWL. This mapping also allows us to apply existing Semantic Web tools and techniques to OBO. We show that Semantic Web(More)
Ontology classification—the computation of the subsumption hierarchies for classes and properties—is a core reasoning service provided by all OWL reasoners known to us. A popular algorithm for computing the class hierarchy is the so-called Enhanced Traversal (ET) algorithm. In this paper we present a new classification algorithm that attempts to address(More)
One of the core services provided by OWL reasoners is classification: the discovery of all subclass relationships between class names occurring in an ontology. Discovering these relations can be computationally expensive, particularly if individual subsumption tests are costly or if the number of class names is large. We present a classification algorithm(More)
This paper presents a simple data model for the representation of OWL ontologies (including the new features of OWL 1.1). The model is built from basic structures native to all common programming environments, so it can be used directly as an API for ontology analysis and manipulation. Furthermore, serialization of these structures using the(More)
HermiT is a reasoner for the Description Logic SHOIQ +. The system is based on a novel " hypertableau " calculus and includes a number of new optimizations. HermiT demonstrates significantly faster performance when classifying large and complex ontologies than other state-of-the-art reasoners. HermiT is also the first reasoner able to classify a number of(More)