Where Porceddu is better than Pasta (DISCUSSION PAPER) Paolo Ciaccia 1 , Davide Martinenghi 2 , and Riccardo Torlone 3 1 Universit` a di Bologna 2 Politecnico di Milano 3 Universit`a Roma Tre Abstract. Preferences and contexts are fundamental aspects for decid- ing the best choices among possible options. We formalize the problem of propagating preferences from more generic to more specific contexts and study the key properties of propagation within an algebraic framework. 1 Introduction Preferences and their influence on choices have been studied in a variety of fields, including psychology, sociology, economics, artificial intelligence, and data management. In all of the above fields, it is widely recognized that preferences highly depend on the context, as shown in the following example. Example 1. We are ordering food at a restaurant in Italy: normally, then, we prefer pasta to beef. In Sardinia, though, we enjoy “porceddu” more than pasta. During summer, however, our preferred choice is just a fresh salad. As in the example, we consider contexts as states (such as “Italy in summer”) that can be compared via a generalization hierarchy, so that, say, “Sardinia” is more specific than “Italy”. Preferences naturally propagate along the hierarchy, from the more generic to the more specific contexts (a preference defined for Italy normally holds in any Italian place). Things are not that simple, though. Example 2. If we are in Sardinia in the summer, all the preferences given in Example 1 apply, since they refer to more generic contexts. Yet, the preferences defined in “Sardinia” and “Italy in summer” should take precedence over those given for “Italy”, whereas the preference in “Sardinia” is on a par with the pref- erence in “Italy in summer”. Then, porceddu and salad are the best alternatives, since no other food is preferable to them in the given context. Our research provides a principled approach to context-aware preference propa- gation. We develop a general framework whose only requirements are as follows: – the contexts belong to a poset, i.e., a set C with a (strict) partial order relation ă C on its elements: c 1 ă C c 2 means that the context c 1 is more specific than the context c 2 (and that c 2 is more generic than c 1 ); Copyright c  2020 for this paper by its authors. Use permitted under Creative Com- mons License Attribution 4.0 International (CC BY 4.0). This volume is published and copyrighted by its editors. SEBD 2020, June 21-24, 2020, Villasimius, Italy.