In the market of goods and services, the forms of market, according to these three characteristics, are the following ones: Perfect competition: infinite number of firms, homogeneous product, and do not exist barriers to the entrance of firms; Monopoly: an only company, product without next substitutes, with barriers to the entrance of new firms; Monopolstica competition (or imperfect): innumerable companies, differentiated product, exempt access of firms to the market; Oligopoly: small number of companies who dominate the market, the products can homogeneous or be differentiated, with barriers to the entrance of new companies. Similarly, in the market of production factors, also we define the forms of market in perfect competition, imperfect competition, monopoly and oligopoly in the supply of insumos. 3. Types of market structure Perfect competition One characterizes for the existence of innumerable purchasers and salesmen, where no company obtains to have influence on the market price. The products elaborated they are homogeneous, being substitute perfect between itself as well as it exists complete information and knowledge on the price of the product on the part of the producers and the consumers.
It is the ideal model of market, therefore the entrance and the exit of firms in the market are free, that is, it does not have barriers. The entrepreneurs always maximize profit and the consumers maximize satisfaction. the consumers and salesmen have access to all information, without costs. Some examples next to the perfect competition are the producers of hortalias and the salesmen of picol in a leisure area. A characteristic of this market is that, in long stated period does not exist extra profits, but only the calls normal profits, that represent the implicit remuneration of the entrepreneur Monopoly Extreme case of basic classic structure. Situation of a market where competition does not exist in offers. The sector is constituted of an only firm, because an only producer exists that it carries through all the production, that is, situation where a company dominates the production or commerce of a raw material, product or service alone and that, therefore, can establish the price to the will.