Illegal migrants supply a valuable productive input: effort. But their status as illegals means that these migrants face a strictly positive probability of expulsion. A return to their country of origin entails reduced earnings when the wage at origin is lower than the wage at destination. This...

This paper asks whether population growth is conducive to the sustainability of cooperation. A simple model is developed in which farmers who live around a circular lake engage in trade with their adjacent neighbors. The payoffs from this activity are governed by a prisoner's dilemma "rule of...

Illegal migrants supply a valuable productive input: effort. But their status as illegals means that these migrants face a strictly positive probability of expulsion. A return to their country of origin entails reduced earnings when the wage at origin is lower than the wage at destination. This...

Consider a population of farmers who live around a lake. Each farmer engages in trade with his m adjacent neighbors, where m is termed the "span of interaction". Trade is governed by a prisoner's dilemma "rule of engagement". A farmer's payoff is the sum of the payoffs from the m prisoner's...