<P> In microeconomics, the law of demand states that, "conditional on all else being equal, as the price of a good increases (↑), quantity demanded decreases (↓); conversely, as the price of a good decreases (↓), quantity demanded increases (↑)". In other words, the law of demand describes an inverse relationship between price and quantity demanded of a good . The factors held constant refer to other determinants of demand, such as the prices of other goods and the consumer's income . There are, however, some possible exceptions to the law of demand, such as Giffen goods and Veblen goods . </P> <P> Mathematically, the inverse relationship described by the law of demand may be expressed as: </P>

Demand which does not obey the law of demand is called