Between Belief Bases and Belief Sets: Partial Meet Contraction

Yuri D. Santos, Márcio Moretto Ribeiro, Renata Wassermann

Abstract:

In belief revision, the result of a contraction should be a logically closed set (closure) such that the input is not inferred (success). Traditionally, these two postulates depend on the same consequence operator.

The present work investigates the consequences of using two different consequence operators for each of these desiderata: the classic Cn to compute success and a second weaker operator to compute the closure. We prove a representation theorem and some other properties for the new contraction.