Belief Change and Dependence
Luís Fariñas del Cerro, Andreas Herzig · 1996
It is a very natural requirement for belief change operations that formulas that are independent of a given update should be preserved. Such a proposal has already been made by Gardenfors (1990). In this perspective we study the links between belief change and the notion of dependence, our aim being to give dependence axioms able to characterize the AGM postulates. Proceeding exactly in the same way as Gardenfors (1988) did in the case of epistemic entrenchment, we show how a given dependence relation can be used to define a contraction operation, and the other way round we show how an independence relation can be obtained from a given contraction operation. The grande finale is a characterization theorem. 1 INTRODUCTION The central question in the theory of belief revision is what is meant by a minimal change of a state of belief. The well-known AGM rationality postulates for contraction (Alchourr'on et al. 1985, Gardenfors 1988) partially answer that question: (K \\Gamm...