Taking Levi Identity Seriously: A Plea for Iterated Belief Contraction

  • Abhaya Nayak
  • Randy Goebel
  • Mehmet Orgun
  • Tam Pham
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4092)


Most work on iterated belief change has focused on iterated belief revision, namely how to compute (K \(^{\rm *}_{x}\))\(^{\rm *}_{y}\). Historically however, belief revision can be defined in terms of belief expansion and belief contraction, where expansion and contraction are viewed as primary operators. Accordingly, our attention to iterated belief change should be focused on constructions like (K \(^{\rm +}_{x}\))\(^{\rm +}_{y}\), (K \(^{\rm --}_{x}\))\(^{\rm +}_{y}\), (K \(^{\rm +}_{x}\))\(^{\rm --}_{y}\) and (K \(^{\rm --}_{x}\))\(^{\rm --}_{y}\). The first two of these are relatively straightforward, but the last two are more problematic. Here we consider these latter, and formulate iterated belief change by employing the Levi identity and the Harper Identity as the guiding principles.


Belief Change Information State Change Iterated Belief Contraction 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Abhaya Nayak
    • 1
  • Randy Goebel
    • 2
  • Mehmet Orgun
    • 1
  • Tam Pham
    • 3
  1. 1.Intelligent Systems Group,Department of Computing, Division of ICSMacquare UniversitySydneyAustralia
  2. 2.Department of Computing ScienceUniversity of AlbertaEdmonton, AlbertaCanada
  3. 3.Thomas M. Siebel Center for Computer ScienceUniversity of IllinoisUrbanaUSA

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