Renata Wassermann

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Standard approachs to belief change assume that the underlying logic contains classical propositional logic. Recently there has been interest in investigating approaches to belief change, specifically contraction, in which the underlying logic is not as expressive as full propositional logic. In this paper we consider approaches to belief contraction in(More)
An agent can usually hold a very large number of beliefs. However, only a small part of these beliefs is used at a time. EEcient operations for belief change should aaect the beliefs of the agent locally, that is, the changes should be performed only in the relevant part of the belief state. In this paper we deene a local consequence operator that only(More)
The operation of contraction (referring to the removal of knowledge from a knowledge base) has been extensively studied in the research field of belief change, and different postulates (e.g., the AGM postulates with recovery, or relevance) have been proposed, as well as several constructions (e.g., partial meet) that allow the definition of contraction(More)
We show that Booth et al.’s Horn contraction based on infra-remainder sets corresponds exactly to kernel contraction for belief sets. This result is obtained via a detour through Horn contraction for belief bases, which supports the conjecture that Horn belief change is best viewed as a “hybrid” version of belief set change and belief base change. Moreover,(More)
In this paper some ideas for adding structure to belief bases are presented. Structured belief bases can be seen as graphs, where each node is a belief and two nodes are adjacent if and only if they are related. Some notions of relatedness are deened. We then show how this extra structure can be used for implementing local change as deened in HW98].
Previous works have shown that the AGM theory cannot be used as the basis for defining contraction operators for several ontology representation languages. In this paper, we examine the postulate of relevance which has been proposed in the belief revision literature as a more intuitive alternative to the AGM postulate of recovery. Even though relevance and(More)