Models for relevant modal logics

Fuhrmann, André

doi:10.1007/bf00370161

Cited by 40 publications

(27 citation statements)

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“…As already mentioned, it is both necessary and sufficient to withdraw either A or B (or both) from a belief set K in order to withdraw A A B from K. Indeed, it is hardly conceivable what a difference there should be between an intention or instruction to withdraw A A B and an intention or instruction to withdraw at least one of A and B, with afree choice which of the conjuncts to withdraw. In the following, our guiding hypothesis is that a contraction with respect to a conjunction just is the same as a (finite) choice contraction (this term is due to Fuhrmann 1988). But be cautious.…”

Section: Postulates For Generalized Epistemic Entrenchmentmentioning

confidence: 99%

Preferential belief change using generalized epistemic entrenchment

Rott

1992

J Logic Lang Inf

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Abstract.A sentence A is epistemically less entrenched in a belief state K than a sentence B if and only if a person in belief state K who is forced to give up either A or B will give up A and hold on to B. This is the fundamental idea of epistemic entrenchment as introduced by G~denfors (1988) and elaborated by Gardenfors and Makinson (1988). Another distinguishing feature of relations of epistemic entrenchment is that they permit particularly simple and elegant construction recipes for minimal changes of belief states. These relations, however, are required to satisfy rather demanding conditions. In the present paper we liberalize the concept of epistemic entrenchment by removing connectivity, rainimality and maximality conditions. Correspondingly, we achieve a liberalization of the concept of rational belief change that does no longer presuppose the postulates of success and rational monotony. We show that the central results of Gardenfors and Makinson are preserved in our more flexible setting. Moreover, the generalized concept of epistemic entrenchment turns out to be applicable also to relational and iterated belief changes.

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Section: Postulates For Generalized Epistemic Entrenchmentmentioning

confidence: 99%

Preferential belief change using generalized epistemic entrenchment

Rott

1992

J Logic Lang Inf

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“…Belief revisions constructed according to the Levi identity make use of negations, and there does not seem to be a straightforward way to avoid this. 4 At last, we should like to give two warnings. The connective-free formulation of epistemic entrenchment relations and theory contractions is only a by-product of this paper, slightly improving on the presentation in [23].…”

Section: Resultsmentioning

confidence: 99%

“…In the research program initiated by AlchourrSn, Giirdenfors and Makinson ([3]; for excellent surveys, see [6] and [16]), belief states are identified with belief sets, and inputs are single sentences. Still working in broadly the same research program, Fuhrmann [4,5] and Hansson [9,10,11] offer modetlings for two important generalizations. They investigate what happens when belief states are identified with belief bases (with belief sets as special eases) and when the input comes in sets of sentences (with singletons as special cases).…”

Section: Dynamicsmentioning

confidence: 99%

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Modellings for belief change: Base contraction, multiple contraction, and epistemic entrenchment (preliminary report)

Rott

Lecture Notes in Computer Science

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Abstract. This paper draws a distinction between the set of explicit beliefs of a reasoner, the "belief base", and the beliefs that are merely implicit. We study syntax-based belief changes that are governed exclusively by the structure of the belief base. In answering the question whether this kind of belief change can be reconstructed with the help of something like an epistemic entrenchment relation in the sense of G~rdenfors and Makinson [8], we extract several candidate relations from a belief base. The answer to our question is negative, but an approximate solution is possible, and in some cases the agreement is even perfect. Two interpretations of the basic idea of epistemic entrenchment are offered. It is argued that epistemic entrenchment properly understood involves multiple belief changes, i.e., changes by sets of sentences. Since none of our central definitions presupposes the presence of propositional connectives in the object language, the notion of epistemie entrenchment becomes applicable to the style of knowledge representation realized in inheritance networks and truth maintenance systems.

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“…We do not treat such systems explicitly here, but the details are straightforwardly supplied; they essentially follow the scheme explained in Fuhrmann (1990). relevant logics weaker or stronger than R).…”

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confidence: 99%