This document discusses different types of market structures:
1. Perfect competition is characterized by many small sellers of identical products, price taking behavior, freedom of entry and exit. Potatoes sold at markets are an example.
2. Monopoly is dominated by a single seller of a unique product where entry is restricted, like Gillette razor blades.
3. Monopolistic competition involves differentiated products that are close substitutes, like various shoe brands.
4. Oligopoly has a small number of interdependent sellers that recognize how their actions impact rivals, like instant noodle brands in India. Duopoly is a specific type of oligopoly with two dominant firms, like Pepsi and Coke in soft drinks