Law of supply


The law of supply is a fundamental principle of economic theory which states that, keeping other factors constant, an increase in price results in an increase in quantity supplied. In other words, there is a direct relationship between price and quantity: quantities respond in the same direction as price changes. This means that producers are willing to offer more of a product for sale on the market at higher prices by increasing production as a way of increasing profits.
In short, the law of supply is a positive relationship between quantity supplied and price and is the reason for the upward slope of the supply curve.

Mathematical definition

In non-differentiable terms, the law of supply can be expressed as:
where y is the amount that would be supplied at some price p, and y' is the amount that would be supplied at some other price p' . Thus for example if p > p' then y > y' .