Market enⅤ Ironments ◆ Monopoly(垄断): Just one selller 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 othersMarket 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