Is Indeed Fish the Best Choice in Rimini?

Preferences depend on the context. For instance, given that it is at seaside, we usually prefer fish to meat for a dinner in Rimini, while probably preferences would be different if we are in Bressanone. On the other hand, Rimini is in Romagna and so the famous “Piadina romagnola” would also be a good choice. In a scenario like this, in which preferences are defined in different contexts, we address the problem of inferring which are the preferences that should be used for answering queries in a given context. To this end we formulate a set of intuitive propagation principles dictating how preferences should be combined, among which the one stating that if a conflict arise, then the more specific context prevails. We then define precise syntactical conditions that expressions respecting the propagation principles should satisfy, and provide a canonical way for doing so. Finally, we consider the well-known Pareto and Prioritized operators and discuss how they implement the proposed framework.