We consider rules (strategies, commitments, contracts, or computer programs) that make behavior contingent on an opponent’s rule. The set of perfectly observable rules is not well defined. Previous contributions avoid this problem by restricting the rules deemed admissible. We instead limit...

According to the Framework Convention on Climate Change, global collective action is needed to stabilize “greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous [our emphasis] anthropogenic interference with the climate system.” The Framework Convention thus...

Nash proposed an interpretation of mixed strategies as the average pure-strategy play of a population of players randomly matched to play a normal-form game. If populations are finite, some equilibria of the underlying game have no such corresponding “mass-action” equilibrium. We show that...

In public good games, voluntary contributions tend to start off high and decline as the game is repeated. If high contributors are matched, however, contributions tend to stay high. We propose a formalization predicting that high contributors will self-select into groups committed to charitable...

Altruists and envious people who meet in contests are symbionts. They do better than a population of narrowly rational individuals. If there are only altruists and envious individuals, a particular mixture of altruists and envious individuals is evolutionarily stable.

Despite the growing concern about actual on-going climate change, there is little consensus about the scale and timing of actions needed to stabilise the concentrations of greenhouse gases. Many countries are unwilling to implement effective mitigation strategies, at least in the short-term, and...

We investigate situations in which players make costly contributions as group members in a group conflict, and at the same time engage in contest with fellow group members to appropriate the possible reward. We introduce within group power asymmetry and complementarity in members’ efforts, and...

We estimate by means of indirect inference a structural economic model where firms’ exit and investment decisions are the solution to a discrete-continuous dynamic programming problem. In the model the exit probability depends on the current capital stock and a measure of short-run...