What are the characteristics and assumptions of the oligopoly model?

A good example of an oligopoly would be the gasoline/petrolium industry. Typically, you only see a finite amount of suppliers selling gasoline. In the U.S, you might see Chevron, BP, Shell, etc. and they are all selling essentially the same product and all for around the same price. There is a lot of price collusion in oligopolies. Basically, if one producer tries to undercut the competition they can risk being squeezed out of the industry, and if they try to over sell their product they may risk losing a tremendous amount of business.