4 main theories involved with oligopoly pricing are as follows:
Price Competition deals with offering discounts on the prices of a particular product or a series of products, in an attempt to generate more market demand of those products. On the other hand, Non-price Competition concentrates on several other strategies to boost up the market shares.
The dominance of one firm in the oligopolistic market results in price leadership. Firms having less market shares only follow the prices fixed by leaders.