Ullrich Hustadt

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Data complexity of reasoning in description logics (DLs) estimates the performance of reasoning algorithms measured in the size of the ABox only. We show that, even for the very expressive DL SHIQ, satisfiability checking is data complete for NP. For applications with large ABoxes, this can be a more accurate estimate than the usually considered combined(More)
As applications of description logics proliferate, efficient reasoning with knowledge bases containing many assertions becomes ever more important. For such cases, we developed a novel reasoning algorithm that reduces a $\mathcal{SHIQ}$ knowledge base to a disjunctive datalog program while preserving the set of ground consequences. Queries can then be(More)
As applications of description logics proliferate, efficient reasoning with large ABoxes (sets of individuals with descriptions) becomes ever more important. Motivated by the prospects of reusing optimization techniques from deductive databases, in this paper, we present a novel approach to checking consistency of ABoxes, instance checking and query(More)
We present TeMP—the first experimental system for testing validity of monodic temporal logic formulae. The prover implements fine-grained temporal resolution. The core operations required by the procedure are performed by an efficient resolution-based prover for classical first-order logic. 1 Monodic First-Order Temporal Logic First-Order Temporal Logic,(More)
This paper reports on an empirical performance analysis of four modal theorem provers on benchmark suites of randomly generated formulae. The theorem provers tested are the Davis-Putnam-based procedure Ksat, the tableaux-based system KRIS, the sequent-based Logics Workbench, and a translation approach combined with the rst-order theorem prover SPASS. Our(More)