Strategy-proofness and essentially single-valued cores revisited
Article [Version of Record]
Is part ofCahier de recherche ; no. 2014-02.
Publisher(s)Université de Montréal. Département de sciences économiques.
We consider general allocation problems with indivisibilities where agents' preferences possibly exhibit externalities. In such contexts many different core notions were proposed. One is the gamma-core whereby blocking is only allowed via allocations where the non-blocking agents receive their endowment. We show that if there exists an allocation rule satisfying ‘individual rationality’, ‘efficiency’, and ‘strategy-proofness’, then for any problem for which the gamma-core is non-empty, the allocation rule must choose a gamma-core allocation and all agents are indifferent between all allocations in the gamma-core. We apply our result to housing markets, coalition formation and networks.