We provide a new proof of the non-emptiness of approximate cores of games with many players of a finite number of types. Earlier papers in the literature proceed by showing that, for games with many players, equal-treatment cores of their "balanced cover games", which are non-empty, can be...

Top responsiveness is introduced by Alcalde and Revilla [Journal of Mathematical Economics 40 (2004) 869-887] as a property which induces a rich domain on players's preferences in hedonic games, and guarantees the existence of core stable partitions. We strengthen this observation by proving the...

This chapter surveys the sizable and growing literature on coalition formation. We refer to theories in which one or more groups of agents (“coalitions”) deliberately get together to jointly determine their actions. The defining idea of a coalition, in this chapter, is that of a group which...

Top responsiveness is introduced by Alcalde and Revilla [Journal of Mathematical Economics 40 (2004) 869-887] as a property which induces a rich domain on players's preferences in hedonic games, and guarantees the existence of core stable partitions. We strengthen this observation by proving the...

We provide a new proof of the non-emptiness of approximate cores of games with many players of a finite number of types. Earlier papers in the literature proceed by showing that, for games with many players, equal-treatment cores of their "balanced cover games", which are non-empty, can be...

When allocating indivisible objects, agents might have equal priority rights for some objects. A common practice is to break the ties using a lottery and randomize over deterministic allocation mechanisms. Such randomizations usually lead to unfairness and inefficiency ex-ante. We propose a...

We consider house allocation problems (Shapley and Scarf, 1974) with strict preferences. We introduce a new axiom called pre-exchange-proofness, which states that no pair of agents gain by exchanging their endowments with each other prior to the operation of the chosen rule. We establish that a...

We study the existence of group strategy-proof stable rules in many-to-many matching markets under responsiveness of agents' preferences. We show that when firms have acyclical preferences over workers the set of stable matchings is a singleton, and the worker-optimal stable mechanism is a...

In ordinal (probabilistic) assignment problems, each agent reports his preference rankings over objects and receives a lottery defined over those objects. A common efficiency notion, sd-efficiency, is obtained by extending the preference rankings to preferences over lotteries by means of...