We show that, when bidders have continuous valuations, any ex post equilibrium in an ex post individually rational query auction can only be ex post efficient when the running timeof the auction is infinite for almost all realizations of valuations of the bidders. We also show that this result...

In multi-unit (procurement) auctions winning multiple contracts can lead to cost advantages due to synergies. As an example one can think of procurement auctions where construction firms have returns to scale for investments in specialized equipments and workers that are required in large-scale...

This paper studies the sales of a single indivisible object where bidders have continuous valuations. In Grigorieva et al. [13] it was shown that, in this setting, query auctions necessarily allocate inefficiently in equilibrium. In this paper we propose a new sequential auction, called the...

This paper examines collusion among firms whose discount factors are private information. Mutual uncertainty regarding intentions to restrict competition might undermine the possibility of tacit collusion. Firms that want to collude may, however, reveal their intentions by consciously acting in...

We show that synergies enhance bidding competition to such an extent that they are a curse rather than a blessing for the bidders; they may even induce serious bankruptcy problems.

Under a k-approval scoring rule each agent attaches a score of one to his k most preferred alternatives and zero to the other alternatives. The rule assigns the set of alternatives with maximal score. Agents may extend preferences to sets in several ways: they may compare the worst alternatives,...

The Rubinstein alternating offers bargaining game is reconsidered under the assumption that each player is loss averse and the associated reference point is equal to the highest turned down offer of the opponent in the past. This makes the payoffs and therefore potential equilibrium strategies...

Voting problems with a continuum of voters and finitely many alternatives are considered. The classical Arrow and Gibbard-Satterthwaite theorems are shown to persist in this model, not for single voters but for coalitions of positive size. The emphasis of the study is on strategic...

Effectivity functions for finitely many players and alternatives are considered. It is shown that every monotonic and superadditive effectivity function can be augmented with equalchance lotteries to a finite lottery model---i.e., an effectivity function that preserves the original effectivity...