Dutch Social Choice Colloquium
dutch landscape

The following meetings of the Dutch Social Choice Colloquium are currently planned:

Maastricht: Friday, 18 January 2019

Speakers: Kristof Bosmans, Bettina Klaus, Flip Klijn, Jordi Massó, Ton Storcken
Location: Room A1.22, Tongersestraat 53, Maastricht (directions)
Host: Hans Peters (Maastricht University)


13:30-14:15 Bettina Klaus (University of Lausanne)
Random Matching under Priorities: Stability and No Envy Concepts
Abstract: We consider stability concepts for random matchings where agents have preferences over objects and objects have priorities for the agents. When matchings are deterministic, the standard stability concept also captures the fairness property of no (justified) envy. When matchings can be random, there are a number of natural stability / fairness concepts that coincide with stability / no envy whenever matchings are deterministic. We formalize known stability concepts for random matchings for a general setting that allows weak preferences and weak priorities, unacceptability, and an unequal number of agents and objects. We then present a clear taxonomy of the stability concepts and identify logical relations between them. Furthermore, we provide no envy / claims interpretations for some of the stability concepts that are based on a consumption process interpretation of random matchings. Finally, we present a transformation from the most general setting to the most restricted setting, and show how almost all our stability concepts are preserved by that transformation. (Based on joint work with Haris Aziz.)
14:15-15:00 Flip Klijn (Institute for Economic Analysis, Barcelona)
Approaching Mutually Best in Matching Markets: Rank-Fairness and Size of the Core
Abstract: This paper studies the one-to-one two-sided marriage model of Gale and Shapley (1962). If agents' preferences exhibit mutually best, there is a unique stable matching that is trivially rank-fair (i.e., in each matched pair the agents assign one another the same rank). We introduce two types of distances that measure to what extent a preference profile violates mutually best. We study whether the size of the core and the rank-unfairness of stable matchings can be bounded in terms of the distances to mutually best. Our findings are negative if we do not make additional assumptions on the domain of preferences profiles. We obtain positive results on the domain of horizontal heterogeneity. (Based on joint work with Christopher Kah and Markus Walzl.)
15:00-15:30 Coffee Break
15:30-16:15 Kristof Bosmans (Maastricht University)
Failure to Compensate or Failure to Reward? A Decomposition of Inequality of Opportunity
Abstract: We decompose inequality of opportunity into compensation and reward components. The former component measures the unfair inequality due to circumstances and the latter component measures the deviation from the fair inequality stemming from the exercise of responsibility. Our analysis illuminates the connection between the liberal and utilitarian approaches to inequality of opportunity measurement. (Based on joint work with Z. Emel Öztürk.)
16:15-17:00 Ton Storcken (Maastricht University)
An Axiomatic Characterization of Slater Rule and Kemeny Rule
Abstract: Slater rule and Kemeny rule are characterized by similar sets of conditions. Moreover, these characterizations are deduced along a similar line of proof. The characterizing conditions are neutrality, a monotonicity condition, either being tournamental or weighed tournamental and either moderately swinging or slowly swinging. Being (weighed) tournamental relates a collective decision rule to the pairwise (weighed) majority relations. Moderately and slowly swinging demands that these rules gradually change their outcomes. We also address the independence of these conditions. (Based on joint work with Burak Can and Mohsen Pourpouneh.)
17:00-17:15 Coffee Break
17:15-18:00 Jordi Massó (Universitat Autònoma de Barcelona)
On Strategy-Proofness and Semilattice Single-Peakedness
Abstract: We study social choice rules defined on the domain of semilattice single-peaked preferences. We characterize the class of strategy-proof rules that are also tops-only, anonymous and unanimous. These rules are deeply related to the supremum of the underlying semilattice structure. (Based on joint work with Agustín Bonifacio.)