We extend the models in ("Competition in two-sided markets" of Armstrong (2006, Rand Journal of Economics) by adding within-group externalities. In the monopoly and duopoly cases, positive within-group externalities reduce the price of the own group. Negative externalities have an opposite price...

We analyze the behavior of producers who compete through price competition in a social environment from a sociological point of view. The standard model of Bertrand price competition is enriched with producers who follow a "Win Cooperate, Lose Defect" (WCLD) strategy. This strategy is a...