I have been studying the following work on description logic, which is closely related to my main work on extensions of order-sorted logic and logic programming [4, 3, 2]. Title: Negation in Description Logics: Contraries, Contradictories and Subcontraries (under submission) Abstract: We propose an alternative description logic ALC∼ with classical negation and strong negation. In particular, we...

Separation logic is a spatial logic for reasoning locally about heap structures. A decidable fragment of its assertion language was presented in [1], based on a bounded model property. We exploit this property to give an encoding of this fragment into a first-order logic containing only the propositional connectives, quantification over the natural numbers and equality. This result is the first...

We compare and contrast Description Logic (DL) and Order-Sorted Feature (OSF) Logic from the perspective of using them for expressing and reasoning with knowledge structures of the kind used for the Semantic Web. Introduction The advent of the Semantic Web has spurred a great deal of interest in various Knowldege Representation formalisms for expressing, and reasoning with, so-called formal ont...

The word 'logic' in the title of this chapter is ambiguous. In its first meaning, a logic is a collection of closely related artificial languages. There are certain languages called first-order languages, and together they form first-order logic. In the same spirit, there are several closely related languages called modal languages, and together they form modal logic. Likewise second-order logi...

Nowadays planning systems are usually based on partially order sets of actions as these sets specify necessary ordering constraints but do not commit otherwise. While computing these sets one usually maintains lists of links in order to detect potential threats. As shown in this paper these maintenance operations are unneccessary if the preconditions as well as eeects of actions are modelled as...