We consider collective decisions made by agents whose preferences and power depend on past events and decisions. Faced with an ineffcient equilibrium and an opportunity to commit to a policy, can the agents reach an agreement on such a policy? Under an intuitive condition linking power...

A frequently heard explanation for the underdeveloped metro system in Rome is the following one: "If we tried to build a new metro line, it would probably be stopped by archeological finds that are too valuable to destroy, so the investment would be wasted." This statement, which seems...

The ways of decision making within the EU have significantly changed in the last decades: the rule of unanimity has been more and more substituted by majority voting in order to speed up decision-making processes in a Union of 27 heterogeneous member states. A third possibility is now offered by...

We investigate the computational complexity of several decision problems in hedonic coalition formation games and demonstrate that attaining stability in such games remains NP-hard even when they are additive. Precisely, we prove that when either core stability or strict core stability is under...

We consider cooperative games with transferable utility (TU-games), in which we allow for a social structure on the set of players. The social structure is utilized to refine the core of the game. For every coalition the relative strength of a player within that coalition is induced by the...

Many economic and social situations can be represented by a digraph. Both axiomatic and iterativemethods to determine the strength or power of all the nodes in a digraph have been proposed inthe literature. We propose a new method, where the power of a node is determined by both thenumber of its...

We analyse procurement auctions in which sellers are distinguished on the basis of the ratios of quality per unit of money that they offer. Sellers are privately informed on the offered quality of the technology or good. We assume that the procurer cannot perfectly identify the best offer. Thus,...

We study decision making processes with non-standard all-pay structures. We motivate this interest through a group of regulatory, political, legal, military, and economic applications where individual actions determine the consequences for a larger group or the public. The common features of...

We propose a simple mechanism providing incentives to reduce harmful emissions to their efficient level without infracting upon productive efficiency. The mechanism employs a contest creating incentives among participating nations to simultaneously exert efficient productive and efficient...

How should we evaluate the welfare implications of improvements to safety technologies in the presence of offsetting behavior? We model this problem as a symmetric game in which each player's payoff depends on his own action and the average action of the other players, and analyze under which...