Zax zeeliin Shinj

The document summarizes key concepts about imperfect competition, including monopolistic competition and oligopoly. It discusses: 1) the characteristics of monopolistic competition as many small differentiated firms that engage in non-price competition, 2) how monopolistically competitive firms are price makers that follow marginal revenue = marginal cost, and 3) how in the long run they earn only normal profits. It then covers: 4) the characteristics of oligopoly including few firms, mutual interdependence, and high barriers to entry, 5) how oligopolists may use price leadership or form cartels to influence prices.