In 
economics, 
perfect competition is a 
market form in which no producer or consumer has the power to influence prices in the market. This leads to an outcome which is efficient, according to the economic definition of 
pareto efficiency.  The analysis of perfectly competitive markets provides the foundation of the theory of 
supply and demand.  One example of perfect competition in the real world is the agricultural industry, whose large amount of suppliers, relatively inelastic 
demand, and almost perfectly substitutable product makes it a close approximation of the perfect competition model.
A market is said to be one with perfect competition if:
- There are a large number of small producers and consumers on a given market
 - None of the producers or consumers can influence the price on their own
 - Goods and services are perfect substitutes[?] -- they are homogeneous
 - All resources (including information) are perfectly mobile
 - Transaction costs are zero
 - The price is determined at the level which equates supply and demand, and moves instantaneously to equilibrium
 
See also: Microeconomics, other market forms
 
All Wikipedia text 
is available under the 
terms of the GNU Free Documentation License