and transportation costs are too high, the possibility of switching is small. Enterprises entering the monopolistic competition market may realize profit increase or loss in the short term, but will realize normal profit in the long run. Because if the price of the enterprise is high enough to offset the fixed cost above the marginal cost, it will attract the enterprise to enter the market to obtain more profits. Once the enterprise enters the market, it will occupy more market share by lowering the product price until the profit reaches 0. If the firm prices above marginal cost but below fixed cost, the firm loses money and some firms exit. These companies that no longer compete for market share allow those that remain to regain market share and survive. Furthermore, each firm shares a small percentage of the total monopolistic market and hence, has limited control over the prevailing market price. Thus, each firms' demand curve (unlike perfect competition) is downward sloping, rather than flat. Additionally, cross-price elasticities of demand are large (but not infinite). Production costs are above what may be achieved by perfectly competitive firms, but society benefits from the product differentiation. If the number of enterprises in monopolistic competition industry increases and the degree of product differentiation is weakened, then the enterprise is closer to pure competition. The main difference between monopoly competition and perfect competition lies in the paradox of excess capacity and price exceeding marginal cost. Oligopoly In an oligopoly market structure, the market is supplied by a small number of firms (more than 2). Moreover, there are so few firms that the actions of one firm can influence the actions of the other firms. Due to the small number of sellers in the market, any adjustment of product quantity and pricing by an enterprise will affect its competitors and thus affect the supply and pricing of the whole market. Oligopolies generally rely on non-price weapons, such as advertising or changes in product characteristics. Several large companies hold large market shares in industrial production, each facing a downward sloping demand, and the industry is often characterized by extensive non-price competition. The oligopoly considers price cuts to be a dangerous strategy. Businesses depend on each other. Under this market structure, the differentiation of products may or may not exist. The product they sell may or may not be differentiated and there are barriers to entry: natural,