The supply function is the mathematical expression of the relationship between supply and those factors that affect the willingness and ability of a supplier to offer goods for sale
SX = Supply of goods
PX = Price
PF = Factor input employed (used) for production.
Raw material
Human resources
Machinery
O = Factors outside economic sphere.
T = Technology.
t = Taxes.
S = Subsidies
There is a functional (direct) relationship between price and supply.