A model of a population with a Local Interaction structure is presented. Individuals interact with others in a given Interaction neighborhood to obtain their payoff. Individuals either imitate or else they die and are replaced by one of their neighbors in another neighborhood- the Propagation...

In a population with a local interaction structure, where individuals interact with their neighbors and learning is by way of imitating a successful neighbor, cooperation is shown to be a stable strategy that cannot easily be eliminated from the population.

The authors study a population of agents, each of whom can be an altruist or an egoist. Altruism is a strictly dominated strategy. Agents choose their actions by imitating others who earn high payoffs. Interactions between agents are local, so that each agent affects, and is affected by, only...

We show, that Strategy profile of a normal form game is proper if and only if it is quasiperfect in every extensive form (with that normal form). Thus, properness requires optimality along a sequence of suppol ting trembles, while sequentiality only requires optimality in the limit. A...