We extend different Description Logics by concrete domains (such as integers and reals) and by aggregation functions over these domains (such as min;max; count; sum), which are usually available in database systems. On the one hand, we show that this extension may lead to undecidability of the basic inference problems satisfiability and subsumption. This is true even for a very small Descriptio...

We introduce a predictive concept recognition methodology for description logics based on a new closed terminology assumption. During knowledge engineering, our system adopts the standard open terminology assumption as it automatically classifies concept descriptions into a taxonomy via subsumption inferences. However, for applications like configuration, the terminology becomes fixed during pr...

We introduce LIMBO, a reasoning system for limited belief. The system features a highly expressive language with first-order quantification, functions and equality, sorts, and introspective belief modalities. Reasoning is based on clause subsumption, unit propagation, and case splits. Decidability and sometimes even tractability is achieved by limiting the number of case splits. This demo illus...

This paper presents a set description logic with subsorts, feature selection (the inverse of unary function application), agreement, intersection , union and complement. We deene a model theoretic open world semantics and show that sorted feature structures constitute a canon-ical model, that is, without loss of generality subsumption and consistency of set descriptions can be considered with r...

We show how a tableaux algorithm for SHIQ can be extended to support role boxes that include range and domain axioms, prove that the extended algorithm is still a decision procedure for the satisfiability and subsumption of SHIQ concepts w.r.t. such a role box, and show how support for range and domian axioms can be exploited in order to add a new form of absorption optimisation called role abs...