AGM contraction is not reconstructible as a descriptor operation

摘要

Centrolinear belief revision is based on a linear ordering of a set consisting of the belief sets that are potential outcomes of changes in belief. The outcome of any particular change is equal to the highest-ranked among those belief sets that satisfy the success condition of the change in question. In previous work, it has been shown that all transitively relational partial meet revisions are reconstructible as centrolinear operations. Here it is shown that transitively relational partial meet contraction is not in general reconstructible as a centrolinear operation. It is argued that neither partial meet contraction nor the centrolinear operation is a plausible representation of belief contraction. Other ways to represent how we give up beliefs should be explored.