Abstract not found

Abstract not found

. Recently Brass and Dix have introduced the semantics D-WFS for general disjunctive logic programs. The interesting feature of this approach is that it is both semantically and proof-theoretically founded. Any program \Phi is associated a normalform res(\Phi), called the residual program, by a non-trivial bottom-up construction using least fixpoints of two monotonic operators. We show in this paper, that the original calculus, consisting of some simple transformations, has a very strong and appealing property: it is confluent and terminating. This means that all the transformations can be applied in any order: we always arrive at an irreducible program (no more transformation is applicable) and this program is already uniquely determined. Moreover, it coincides with the normalform res(\Phi) of the program we started with. The semantics D-WFS can be read off from res(\Phi) immediately. No proper subset of the calculus has these properties --- only when we restrict to certain subclasse...

In this tutorial-overview, which resulted from a lecture course given by the authors at

The field of theory update has seen some major improvements in what concerns model updating. The update of models is governed by update rules and by inertia applied to the literals not directly aoeected by the update program. This is important but it is still necessary to tackle as well the updating of programs. Some results have been obtained on the issue of updating a logic program which encodes a set of models, to obtain a new program whose models are the desired updates of the initial models. But here the program only plays the rôle of a means to encode the models. A logic program encodes much more than a set of models: it encodes the relationships between the elements of those models. In this dissertation we advocate that the principle of inertia is advantageously applied to the rules of the initial program rather than to the individual literals in a model. Indeed, we show how this concept of program update generalizes simple interpretation update. We will consider both the 2-valued...

The present prolegomena consist, as all indeed do, in a critical discussion serving to introduce and interpret the extended works that follow in this book. As a result, the book is not a mere collection of excellent papers in their own specialty, but provides also the basics of the motivation, background history, important themes, bridges to other areas, and a common technical platform of the principal formalisms and approaches, augmented with examples. In the

Abstract not found

This paper gives a brief high-level description of what has been done in the Disjunctive Logic Programming-project (funded by Deutsche Forschungs-Gemeinschaft), undertaken by the University of Koblenz since July 1995. We present the main ideas, cite the relevant papers and point to the implemented systems and how to access them. This paper also serves as a brief survey of the current status of disjunctive logic programming by highlighting important developments and providing enough pointers for further reading.

In recent years, various formalizations of non-monotonic reasoning and different semantics for normal and disjunctive logic programs have been proposed, including autoepistemic logic, circumscription, CWA, GCWA, ECWA, epistemic specifications, stable, well-founded, stationary and static semantics of normal and disjunctive logic programs. In this paper we introduce a simple non-monotonic knowledge representation framework which isomorphically contains all of the above mentioned non-monotonic formalisms and semantics as special cases and yet is significantly more expressive than each one of these formalisms considered individually. The new formalism, called the Autoepistemic Logic of Knowledge and Beliefs, AELB, is obtained by augmenting Moore's autoepistemic logic, AEL, already employing the knowledge operator , L, with an additional belief operator , B. As a result, we are able to reason not only about formulae F which are known to be true (i.e., those for which LF holds) but also abou...

We describe the elds of disjunctive logic programming and disjunctive deductive databases from the time of their inception to the current time. Contributions with respect to semantics, implementations and applications are surveyed.