We use Scott's domain theory and methods from Reiter's default logic to suggest some ways of modelling default constraints in feature logic. We show how default feature rules, derived from default constraints, can be used to give ways to augment strict feature structures with default information.

Among non-monotonic systems of reasoning, non-monotonic modal logics, and autoepistemic logic in particular, have had considerable success. The presence of explicit modal operators allows flexibility in the embedding of other approaches. Also several theoretical results of interest have been established concerning these logics. In this paper we introduce non-monotonic modal logics based on many...

Nonmonotonic logic programming (NMLP) and inductive logic programming (ILP) are two important extensions of logic programming. The former aims at representing incomplete knowledge and reasoning with commonsense, while the latter targets the problem of inductive construction of a general theory from examples and background knowledge. NMLP and ILP thus have seemingly different motivations and goa...

There are several contexts of non-monotonic reasoning where a prior7 ity between rules is established whose purpose is preventing conflicts. 8 One formalism that has been widely employed for non-monotonic reasoning is 9 the sceptical one known as Defeasible Logic. In Defeasible Logic the tool used 10 for conflict resolution is a preference relation between rules, that establishes the 11 priorit...

This paper discusses the relationship between the property of paraconsistency and Statistical Default Logic, a nonmonotonic logic that models common inference forms found in classical statistical inference such as hypothesis testing and the estimation of a population’s mean, variance and proportions. Statistical Default Logic is paraconsistent in the sense that a set of default inference forms ...

Fifteen years of work on nonmonotonic logic has certainly increased our understanding of the area. However, given a problem in which nonmonotonic reasoning is called for, it is far from clear how one should go about modeling the problem using the various approaches. We explore this issue in the context on two of the best-known approaches, Reiter's default logic 1980] and Moore's autoepistemic l...

We present the proof theory and the model theory of a monotonic framework for default reasoning, and we extend logic programming techniques to this framework. Standard for-malizations of default reasoning do not syntactically separate between hard knowledge and conjectural knowledge. Such a separation is fundamental in our framework. To illustrate our approach, we show how it solves the Yale Sh...

Belief revision has been studied mainly with respect to background logics that are monotonic in character. In this paper we study belief revision when the underlying logic is non-monotonic instead— an inherently interesting problem that is under explored. In particular, we will focus on the revision of a body of beliefs that is represented as a logic program under the answer set semantics, whil...

According to the report on non-monotonic reasoning (Year 1 deliverable), three approaches has been presented: default reasoning, auto-epistemic logic and circumscription. The automation of these non-monotonic reasoning formalisms has been studied and several methods and theorem provers have been proposed, most of them dedicated to default reasoning. For default reasoning, several approaches hav...

When the new research area of logic programming and non-monotonic reasoning emerged at the end of the 1980s, it focused notably on the study of mathematical relations between different non-monotonic formalisms, especially between the semantics of stable models and various non-monotonic modal logics. Given the many and varied embeddings of stable models into systems of modal logic, the modal int...