One of the main ways to specify goals of agents is to use temporal logics. Most existing temporal logics are monotonic. However, in representing goals of agents, we often require that goals be changed non-monotonically. For example, the initial goal of the agent may be to be always in states where p is true. The agent may later realize that under certain conditions (exceptions) it is ok to be i...

In this paper, we describe a system, called TheoryBase, whose goal is to facilitate experimental studies of nonmonotonic reasoning systems. TheoryBase generates test default theories and logic programs. It has an identiication system for generated theories, which allows us to reconstruct a logic program or a default theory from its identiier. Hence, exchanging test cases requires only exchangin...

The idea of only-knowing a collection of sentences has been previously shown to have a close connection with autoepistemic logic. Here we propose a more general account of only-knowing that captures not only autoepistemic logic but default logic as well. This allows us not only to study the properties of default logic in terms of an underlying model of belief, but also the relationship among di...

In this paper ' I ask, and attempt to answer, the following question : What's Wrong with Non-Monotonic Logic? The answer, briefly' is that the motivation behind the wonderfully impressive work involved in its development is based on a confusion of proof-theoretic with epistemological issues.What's wrong with non-monotonic logic (and fo! that matter, with the logic of default reasoning)? The fir...

The non-monotonic reasoning system noMoRe [2] implements answer set semantics for normal logic programs. It realizes a novel, rule-based paradigm to compute answer sets by computing non-standard graph colorings of the block graph associated with a given logic program (see [6, 8, 7] for details). These non-standard graph colorings are called a-colorings or application-colorings since they reflec...

s Axiom sets and their extensions are viewed as functions from the set of formulas in the language, to a set of four truth-values t,f, s for undefined, and k for contradiction. Such functions form a lattice with 'contains less information' as the partial order and 'combination of several sources of knowledge' as the l.u.b. operation We demonstrate the relevance of this approach by giving concis...

In this paper we propose the usage of a framework combining standard deontic logic (SDL) and non-monotonic logic programming – deontic logic programs (DLP) – to represent and reason about normative systems.

We start by defining an approach to non-monotonic prob­ abilistic reasoning in terms of non-monotonic categorical reasoning. We identify a type of non-monotonic proba­ bilistic reasoning, akin to default inheritance, that seems to be commonly found in practice. We formulate this in terms of the Maximization of Conditional Independence (MCI), and identify a variety of applications for this sort ...

Since the earliest formalisation of default logic by Reiter many contributions to this appealing approach to nonmonotonic reasoning have been given. The diierent formalisations are here presented in a general framework that gathers the basic notions, concepts and constructions underlying default logic. Our view is to interpret defaults as special rules that impose a restriction on the juxtaposi...

In this paper we present a logical speciication of data types. This speciication is built upon a previously given speciication for a data type that we want to extend by introducing new constructing objects and deened operations. The extended data type is speciied by superposing a circumscription principle to some speciication axioms. Circumscription formalizes in second-order logic some forms o...