N-firm oligopolies with production adjustment costs: Best responses and equilibrium

N-firm single-product oligopolies will be examined without product differentiation and with production adjustment costs. The best response functions of the firms will be first determined in terms of the outputs of the rest of the industry and the firm's own outputs of the previous time period. This function is always decreasing, not necessarily continuous, and might have two different values. Then the best response will be determined, when the output of the rest of the industry is replaced by the output of the entire industry. We will show that this function might have infinitely many values leading to infinitely many equilibria. A complete description of the equilibrium set will also be given. The theoretical findings will be illustrated with the case of linear price and linear cost functions.