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Selective Credibility-Limited Belief Update

Source

arXiv

arxiv.org/abs/2607.28523v1

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Plain-Language Brief

The paper introduces a new method called Selective Credibility-Limited Belief Update. This method allows an agent to update its beliefs based on changes in the world, by transforming the epistemic input (information) into a weaker form before incorporating it. The paper provides characterizations for this class of update operators and identifies two well-behaved sub-classes. The method is shown to be more general than existing belief update methods, encompassing established approaches while allowing for source-dependent selective acceptance.

What the Document Says

  • Belief update is concerned with changes in an agent's beliefs due to changes in the world.
  • Standard Katsuno-Mendelzon update allows for belief change from every possible world, while credibility-limited belief update restricts this based on each source world.
  • Existing credibility-limited approaches treat epistemic input as indivisible.
  • The paper introduces Selective Credibility-Limited Belief Update, which transforms the epistemic input relative to each source world before performing the update.
  • Semantic and axiomatic characterizations are provided for this class of operators.
  • Two sub-classes are identified: consistency-preserving and maximal consistency-preserving update operators.
  • The method is shown to be more general than existing belief update methods, including Katsuno--Mendelzon belief update as a special case when credibility restrictions are removed and transformation functions are identities.

Key Concepts Mentioned

  • Belief update
  • Credibility-limited belief update
  • Selective Credibility-Limited Belief Update
  • Epistemic input
  • Source world
  • Transformed epistemic input
  • Consistency-preserving update operators
  • Maximal consistency-preserving update operators

Claims Made by the Document

  • Existing credibility-limited approaches treat the epistemic input as an indivisible whole.
  • The proposed framework provides a unified and more expressive account of belief update.
  • Credibility-Limited Belief Update is a special case of the proposed framework.

Evidence Used

  • The text discusses transforming epistemic input relative to each source world before performing the update.
  • The paper provides semantic and axiomatic characterizations of the resulting class of update operators.
  • The text mentions two sub-classes: consistency-preserving and maximal consistency-preserving update operators.

Methods / Approach

UNKNOWN

Limitations Stated by the Authors

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Limitations Noted by the Agent

Agent interpretation — not from the source.

UNKNOWN

Open Questions

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Notes for Future Q&A

May include interpretation. Labeled where it does.

UNKNOWN

Raw Abstract / Excerpt

Belief update concerns changes in an agent's beliefs induced by changes in the underlying world. Standard Katsuno-Mendelzon update assumes that an epistemic input can be incorporated from every initially possible world, whereas credibility-limited belief update restricts, for each source world, the successor worlds regarded as credible or reachable. Nevertheless, existing credibility-limited approaches treat the epistemic input as an indivisible whole, and therefore cannot represent cases in which only part of a compound epistemic input can be realized. We introduce selective credibility-limited belief update, in which the epistemic input is transformed, relative to each source world, into a weaker proxy before the credibility-limited transition is performed. We provide semantic and axiomatic characterizations of the resulting class of update operators. We then identify two well-behaved sub-classes; namely, consistency-preserving update operators, which require every transformed epistemic input to be credible from its source world whenever the original epistemic input is consistent, and maximal consistency-preserving update operators, which additionally require the selected proxy to be maximally informative among the credible consequences of the original epistemic input. Finally, we establish the generality of the proposed framework by showing that credibility-limited belief update is recovered as a special case, while Katsuno--Mendelzon belief update emerges when credibility restrictions are removed and the transformation functions are taken to be identities. These results demonstrate that the framework provides a unified and strictly more expressive account of belief update, encompassing established approaches while supporting source-dependent selective acceptance.