Aggregation of Coarse Preferences

We consider weak preference orderings over a set An of n alternatives. An individual preference is of refinement lindividual preferences; voting rules; aggregation

Aggregation of Coarse Preferences

We consider weak preference orderings over a set An of n alternatives. An individual preference is of refinement ≤ n if it first partitions An into subsets of ‘tied’ alternatives, and then ranks these subsets within a linear ordering. When < n, preferences are coarse. It is shown that, if the refinement of preferences does not exceed , a super majority rule (within non-abstaining voters) with rate 1 − 1/ is necessary and sufficient to rule out Condorcet cycles of any length. It is argued moreover how the coarser the individual preferences, (1) the smaller the rate of super majority necessary to rule out cycles ‘in probability’; (2) the more probable the pairwise comparisons of alternatives, for any given super majority rule

The Informational Basis of the Theory of Fair Allocation

The theory of fair allocation is often favourably contrasted with the social choice theory in the search for escape routes from Arrow's impossibility theorem. Its success is commonly attributed to the fact that it is modest in its goal vis-a-vis social choice theory, since it does not aspire for a full-fledged ordering of options, and settles with a subset of "fair" options. We show that its success may rather be attributable to a broadened informational basis thereof. To substantiate this claim, we compare the informational basis of the theory of fair allocation with the informational requirements of social choice theory.

Multilateral agricultural trade liberalization: The contrasting fortunes of developing countries in the Doha Round

An applied general equilibrium model is used to assess the impact of multilateral trade liberalization in agriculture, with particular emphasis on developing countries. We use original data, and the model includes some specific features such as a dual labor market. Applied tariffs, including those under preferential regimes and regional agreements, are taken into account at the detailed product level, together with the corresponding bound tariffs on which countries negotiate. The various types of farm support are detailed, and several groups of developing countries are distinguished. Simulations give a contrasted picture of the benefits developing countries would draw from the Doha development round. The results suggest that previous studies that have neglected preferential agreements and the binding overhang (in tariffs as well as domestic support), and have treated developed countries with a high level of aggregation have been excessively optimistic about the actual benefits of multilateral trade liberalization. Regions like sub-Saharan Africa are more likely to suffer from the erosion of existing preferences. The main gainers of the Doha round are likely to be developed countries and Cairns group members. Classification-CGE model, Doha Round, agriculture, tariff preferences, domestic support.

Improving package recommendations through query relaxation

Recommendation systems aim to identify items that are likely to be of interest to users. In many cases, users are interested in package recommendations as collections of items. For example, a dietitian may wish to derive a dietary plan as a collection of recipes that is nutritionally balanced, and a travel agent may want to produce a vacation package as a coordinated collection of travel and hotel reservations. Recent work has explored extending recommendation systems to support packages of items. These systems need to solve complex combinatorial problems, enforcing various properties and constraints defined on sets of items. Introducing constraints on packages makes recommendation queries harder to evaluate, but also harder to express: Queries that are under-specified produce too many answers, whereas queries that are over-specified frequently miss interesting solutions. In this paper, we study query relaxation techniques that target package recommendation systems. Our work offers three key insights: First, even when the original query result is not empty, relaxing constraints can produce preferable solutions. Second, a solution due to relaxation can only be preferred if it improves some property specified by the query. Third, relaxation should not treat all constraints as equals: some constraints are more important to the users than others. Our contributions are threefold: (a) we define the problem of deriving package recommendations through query relaxation, (b) we design and experimentally evaluate heuristics that relax query constraints to derive interesting packages, and (c) we present a crowd study that evaluates the sensitivity of real users to different kinds of constraints and demonstrates that query relaxation is a powerful tool in diversifying package recommendations