On Speciicity in Default Logic

Computing Speciicity in Default Reasoning

Default Reasoning with Speci cityPhan

We present a new approach to reasoning with speciicity which subsumes inheritance reasoning. The new approach diiers from other approaches in the literature in the way priority between defaults is handled. Here, it is context sensitive rather than context independent as in other approaches. We show that any context independent handling of priorities between defaults as advocated in the literatu...

Introducing plausibility measures in the processof revision of beliefs through extended logicprogramsBerilhes

A new proposal for incorporating new evidence in an agent's knowledge base is presented in this paper. This proposal is based on a semi-qualitative notion of plausibility and on the abductive explanation for the newly observed fact. Plausibility is determined by speciicity relations between the default rules in the agent's knowledge base and by the agent's contingential knowledge. We demonstrat...

Dialectics and Speciicity: Conditioning in Logic-based Hypothetical Reasoning (preliminary Report)

In this paper we start with defaults as possible hypotheses and prediction as membership in all extensions. It is argued that this is too conservative and does not allow many intuitive answers. We show how viewing membership in all extensions as a form of di-alectic, and adding a notion of conditioning can produce more intuitive answers. Defaults are possible hypotheses for a logical argument t...

Context-dependent reasoning with lexical knowledge using default logic

Lexical knowledge is increasingly important in language engineering. However, it is a dii-cult kind of knowledge to represent and reason with. Existing approaches to formalizing lexical knowledge have used languages with limited expressibility and in particular they have not addressed the context-dependent nature of lexical knowledge. Here we present a framework, based on default logic, called ...