Preference Change Triggered by Belief Change: a Principled Approach

Various tasks need to consider preferences in a dynamic way. To evaluate and classify methods for preference change, we introduce eight properties for preferences evolving after some new fact has been learned. Four properties are concerned with persistence of preferences when something being preferred is (partly) satisfied or dissatisfied, and formalize that preference change indicates that the ideal state has not been reached or has become unreachable. Four other properties are concerned with persistence of preferences when, roughly, the agent learns something she already expected to hold, and formal- izes that preference change is due to surprise. We define a family of preference change operators, parameterized by a revision function on epistemic states and a semantics for interpreting preferences over formulas, and we give conditions on the revision function and the semantics of preference for each of the eight conditions to hold.ou