We characterize the class of symmetric two-player games in which tit-for-tat cannot be beaten even by very sophisticated opponents in a repeated game. It turns out to be the class of exact potential games. More generally, there is a class of simple imitation rules that includes tit-for-tat but...

We show that in symmetric two-player exact potential games, the simple decision rule imitate-if-better cannot be beaten by any strategy in a repeated game by more than the maximal payoff difference of the one-period game. Our results apply to many interesting games including examples like 2x2...

We show that for many classes of symmetric two-player games, the simple decision rule 'imitate-if-better' can hardly be beaten by any strategy. We provide necessary and sufficient conditions for imitation to be unbeatable in the sense that there is no strategy that can exploit imitation as a...

We show that for many classes of symmetric two-player games, the simple decision rule imitate-the-best can hardly be beaten by any other decision rule. We provide necessary and sufficient conditions for imitation to be unbeatable and show that it can only be beaten by much in games that are of...

We compare predictions from a theoretical model based on the structure of the main outdoor retail market in Jerusalem with the results of an empirical analysis of price response to changes in cost. We find that firms without adjacent competition exhibit both upward and downward price rigidity,...

We argue that, in a simple setting, the relation between the intensity of competition and cost-reducing investment is U-shaped. We consider a two-stage game with cost-reducing investments followed by a linear differentiated Cournot duopoly. We first show that, except for firms that are much less...

Using a general two-stage framework, this paper gives sufficient conditions for increasing competition to have negative or positive effects on R&D-investment, respectively. Both possibilities arise in plausible situations, even if one uses relatively narrow definitions of increasing competition....

We examine the interplay of endogenous vertical integration and costreducing downstream investment in successive oligopoly. We start from a linear Cournot model to motivate our more general reducedform framework. For this general framework, we establish the following main results: First,...

The paper characterizes the mixed-strategy equilibria in all-pay auctions with endogenous prizes that depend positively on own effort and negatively on the effort of competitors. Such auctions arise naturally in the context of investment games, lobbying games, and promotion tournaments. We also...

The buyer solicits bids from suppliers with different cost distributions defined by their capacities. The expected market share of each supplier is the ratio of its capacity to the industry capacity. The buyer's optimal reserve price declines with increases in the concentration of the industry....