北大ceer 笔记21.ppt

Chapter Twenty-Two Firm Supply 厂商供给 Structure Market environments Market demand for a competitive firm Short-run supply decision Upward sloping MC curve Shut-down condition Long-run supply decision Comparing long-run and short-run decisions. Producer’s surplus and profits Firm Supply How does a firm decide how much product to supply? This depends upon the firm’s technology market environment goals competitors’ behaviors Market Environments Are there many other firms, or just a few? Do other firms’ decisions affect our firm’s payoffs? Is trading anonymous, in a market? Or are trades arranged with separate buyers by middlemen? Market Environments Monopoly (垄断）: Just one seller that determines the quantity supplied and the market-clearing price. Oligopoly （寡头垄断）: A few firms, the decisions of each influencing the payoffs of the others. Market Environments Dominant Firm: Many firms, but one much larger than the rest. The large firm’s decisions affect the payoffs of each small firm. Decisions by any one small firm do not noticeably affect the payoffs of any other firm. Market Environments Monopolistic Competition （垄断竞争）: Many firms each making a slightly different product. Each firm’s output level is small relative to the total. Pure Competition: Many firms, all making the same product. Each firm’s output level is small relative to the total. Market Environments Later chapters examine monopoly, oligopoly, and the dominant firm. This chapter explores only pure competition. Pure Competition A firm in a perfectly competitive market knows it has no influence over the market price for its product. The firm is a market price-taker. The firm is free to vary its own price. Pure Competition If the firm sets its own price above the market price then the quantity demanded from the firm is zero. If the firm sets its own price below the market price then the quantity demanded from the firm is the entire market quantity-demanded. Pure Competition So what is the de