Seoul subway map for KEVIN R. FOSTER, PH.D. CITY COLLEGE OF NEW YORK oligopoly DESCRIBING A MARKET or industry, an oligopoly exists when there are relatively few firms and many buyers. In such a market environment, each buyer takes the market conditions as given but each firm is aware that its actions will have an effect on its rival’s action. Most goods and services are provided in oligopoly markets rather than perfectly competitive or monopoly markets, and economists have been concerned with oligopoly theory ever since Augustine Cournot’s pioneering work, published in 1838. Even today, the oligopoly question, how prices are determined when there are only a few sellers in the market, is a central area of investigation of the field of INDUSTRIAL ORGANIZATION. Seoul subway map 2016.