CEVAP:

For understanding markets and explaining the behaviors in them, economists have developed four principal models of market structure which are based on four dimensions:
• the number of producers in the market,
• the companies’ degree of pricing power,
• whether the products offered are undifferentiated or differentiated (products that are different but viewed substitutable by customers), and
• the market is consolidated or fragmented (market share for the leading four firms is equal to or less than 40% of total industry sales).