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...

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...

We report on the design of a prototyping component for the theorem prover Isabelle/HOL. Specifications consisting of datatypes, recursive functions and inductive definitions are compiled into a functional program. Functions and inductively defined relations can be mixed. Inductive definitions must be such that they can be executed in Prolog style but requiring only matching rather than unificat...

We provide an extension of universal algebra and its equational logic from first to second order. Conservative extension, soundness, and completeness results are established.

In this paper we define computationally well-behaved versions of classical first-order logic and prove that the validity problem is decidable1.

We consider the EFO fragment of simple type theory, which restricts quantification and equality to base types but retains lambda abstractions and higher-order variables. We show that this fragment enjoys the characteristic properties of first-order logic: complete proof systems, compactness, and countable models. We obtain these results with an analytic tableau system and a concomitant model ex...