Multiprocessor equipment is cheap and ubiquitous now, but users of description logic (DL) reasoners have to face the awkward fact that the major tableau-based DL reasoners can make use only one of the available processors. Recently, researchers have started investigating how concurrent computing can play a role in tableau-based DL reasoning with the intention of fully exploiting the processing ...

We present tableau calculi for some logics of default reasoning, as defined by Kraus, Lehmann and Magidor. We give a tableau proof procedure for preferential and cumulative logics. Our calculi are obtained by introducing suitable modalities to interpret conditional assertions. Moreover, they give a decision procedure for the respective logics and can be used to establish their complexity.

In this paper, we propose a tableau-based technique for reasoning with various distributed DL knowledge bases. This technique can be applied both to DDLs and to new and relevant sublanguages of basic E-connections. Its main advantage is that it is straightforward to implement by extending the existing tableau-based algorithms, as witnessed by our implementation in the Pellet OWL reasoner.

We present the design of a tableau reasoner, called TGC 2, that uses global caching for reasoning in description logics. We briefly describe the ExpTime tableau methods used by TGC 2. We then provide the design principles and some important optimization techniques for increasing the efficiency of the reasoner.

The purpose of this paper is to develop a class of semantic tableau systems for some counterfactual logics. All in all I will discuss 1024 systems. Possible world semantics is used to interpret our formal languages. Soundness results are obtained for every tableau system and completeness results for a large subclass of these.