This document discusses different types of markets:
1) Perfect competition is characterized by many small firms and buyers selling homogeneous products with no barriers to entry. Price is determined by the industry.
2) Imperfect competition includes monopoly, monopolistic competition, and oligopoly. A monopoly has a single seller without substitutes and can influence price. Monopolistic competition has many sellers of differentiated products. Oligopoly has a few dominant firms producing homogeneous or differentiated goods.