Consistency Testing: The RACE Experience

. This paper presents the results of applying RACE, a description logic system for ALCNH R + , to modal logic SAT problems. Some aspects of the RACE architecture are discussed in detail: (i) techniques involving caching and (ii) techniques for dealing with individuals. 1 Introduction to the RACE Architecture The description logic (DL) ALCNH R + [5] extends the logic ALCHf R + (see [8] for a concept consistency calculus) by adding number restrictions. The inference services supported by RACE for TBoxes and ABoxes are described in [6]. In this paper, due to space restrictions, we assume that the reader is familiar with DLs. The ABox consistency algorithm implemented in the RACE system is described as a tableaux calculus in [5]. However, optimized search techniques are required in order to guarantee good average-case performance. The RACE architecture incorporates the following standard optimization techniques: dependencydirected backtracking [12] and DPLL-style semantic bra..