The paper compares two models of evolution in symmetric twoplayergames with incomplete information. One model postulates thatthe type of a player is fixed, and evolution works within types. Inthe other model type-contingent strategies evolve. In the case of twotypes and two strategies it is...

We set up a two-stage game with sequential moves by one altruistic agent andn selfish agents. The rotten kid theorem states that the altruist can only reach her firstbest when the selfish agents move before the altruist. The Samaritan’s dilemma, on theother hand, states that the altruist can...

Noncooperative games in which each player’s payo¤ function depends on anadditively separable function of every player’s choice variable may be transformedinto an aggregative game, which may be analysed using the conceptof ‘share functions’. The resulting approach avoids the...

The rent-seeking model of Tullock (1980) has stimulated a large literature on rent-seekingcontests, of which Hillman (1989) and Nitzan (1994) provide useful surveys. AlthoughTullock's 'winner take all' model has been adapted and extended in numerous ways, thereremain fundamental modeling issues,...

Player i's payoff in a noncooperative game is generally expressed as a function of thevector of strategies of all players. However, in some games - 'simply reducible games' - thepayoff of player i is a function of two arguments - the strategy chosen by i, and the sum ofthe strategies of all...