In an oligopolistic market, firm i and firm j have constant marginal cost = c for an identical good. They compete to set prices Pi and Pj. The demand for total market demand Q, where if
Pi>Pj, the demand for firm i is 0. If
Pi<Pj, the demand for firm i is Q. If
P₁=Pj, then they share the market equally and hence the demand for firm i is
2Q. In equilibrium, the prices of firms i and j are: