Studia Logica

, Volume 73, Issue 2, pp 167–182 | Cite as

Eligible Contraction

  • John Cantwell


When a belief set is contracted only some beliefs are eligible for removal. By introducing eligibility for removal as a new semantic primitive for contraction and combining it with epistemic entrenchment we get a contraction operator with a number of interesting properties. By placing some minimal constraint upon eligibility we get an explicit contraction recipe that exactly characterises the so called interpolation thesis, a thesis that states upper and lower bounds for the amount of information to be given up in contraction. As a result we drop the controversial property of recovery. By placing additional constraints on eligibility we get representation theorems for a number of contraction operators of varying strength. In addition it is shown that recovery contraction is a special case that we get if eligibility is explicitly constructed in terms of logical relevance.

Belief revision Contraction Entrenchment Relevance Recovery 


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Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • John Cantwell
    • 1
  1. 1.The Philosophy UnitThe Royal Institute of TechnologyStockholmSweden

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