Journal of Logic, Language and Information

, Volume 7, Issue 2, pp 127-137

First online:

On the Logic of Theory Change: Contraction without Recovery

  • Eduardo L. FerméAffiliated withGrupo de Investigación y Desarrollo en Inteligencia Artificial (GIDIA), Departamento de Computación, University of Buenos AiresPabellón I Ciudad Universitaria (1428)

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The postulate of Recovery, among the six postulates for theory contraction, formulated and studied by Alchourrón, Gärdenfors and Makinson is the one that has provoked most controversy. In this article we construct withdrawal functions that do not satisfy Recovery, but try to preserve minimal change, and relate these withdrawal functions with the AGM contraction functions.

Theory change AGM theory belief contraction recovery postulate Levi identity Harper identity