Jose Alcalde

Coalition Formation and Stability

This paper studies a class of NTU coalition formation games in which every player’s payoff depends only on the members of her coalition. We identify four natural conditions on individuals’ preferences and show that, under each condition, stable (core) allocations exists.

The minimal overlap rule revisited

This paper provides an analysis of the Minimal Overlap Rule, a solution for bankruptcy problems introduced by O’Neill (1982). We point out that this rule can be understood as a composition of Ibn Ezra’s proposal and the recommendation given by the Constrained Equal Loss Rule. Following an interpretation of bankruptcy problems in terms of TU games, we show that the Minimal Overlap Value is the unique solution for bankruptcy games which satisfies Anonymity and Core Transition Responsiveness.

Pigouvian Taxes: A Strategic Approach

This paper analyzes the problem of designing mechanisms to implement efficient solutions in economies with externalities. We provide two simple mechanisms implementing the Pigouvian Social Choice Correspondence in environments in which coalitions can be formed. Finally, we study economies in which agents are incompletely informed, and provide a mechanism that implements this social choice correspondence in Bayesian equilibrium.

THE ROLE OF UNIONS IN HIRING PROCEDURES FOR JOB MARKETS

This paper studies simple hiring procedures for job markets. We show that when agents act strategically only individually rational outcomes should be expected. Moreover, If agents can form unions, thereby gaining the possibility to commit on the decision to be chosen, only stable allocations are implemented.

Beyond the Spanish MIR with consent: (Hidden) cooperation and coordination in matching

Sequential mechanisms to solve matching problems are useful to promote (hidden) cooperation between agents. Taking as a starting point the MIR mechanism, employed in Spain to match medical students and residency programs (in privately owned hospitals), we find that: (1) In the current system, where the number of students that each program might enroll is limited, the single equilibrium allocation can be unstable. (2) When the above limit is not (formally) imposed,instability is not expected to occur. Nevertheless, the multiplicity of equilibria shows that coordination failure might emerge, generating a social welfare loss. (3) When the role of students and hospitals is reversed in the MIR mechanism, (hidden) cooperation is guaranteed. Moreover, coordination failure disappears.

Equal Awards vs. Equal Losses in Bankruptcy Problems

The Constrained Equal Awards and Equal Losses rules are traditional ways to solve bankruptcy problems. These rules are characterized by two parameters α and β that represent, respectively, the maximum amount a claimant receives, or the maximum amount a claimant loses. Moreover, these rules define a partition in the set of agents: those who are equally rationed, and those sustaining a lower rationing (because their maximal award and maximal loss cannot exceed their claim). We investigate the relationship between α and β, and the corresponding partitions they originate in the set of agents, by using a characteristic τ measuring the relative degree of conflict.

On integration policies and schooling

This paper proposes a reform for school allocation procedures in order to help integration policies reach their objective. For this purpose, we suggest the use of a natural two-step mechanism. The (stable) first step is introduced as an adaptation of the deferred-acceptance algorithm designed by Gale and Shapley (1962), when students are divided into two groups. The (efficient) second step captures the idea of exchanging places inherent to Gales Top Trading Cycle. This latter step could be useful for Municipal School Boards when implementing some integration policies.

Merging and Going Bankrupt: A Neutral Solution

As it is known, there is no rule satisfying Additivity in the complete domain of bankruptcy problems. This paper proposes a notion of partial Additivity in this context, to be called m-additivity. We find that m-additivity, together with two quite compelling axioms, anonymity and continuity, identify the Minimal Overlap rule, introduced by Neill (1982).