A theoretical proof for the mathematical properties of the law of dema
nd is presented. The properties differ significantly from the properti
es of demand functions commonly used in computerized business simulato
rs. Using a probability distribution that has the mathematical propert
ies required by the law of demand, a market demand model is presented.
The new model satisfies economic and marketing theories of consumer b
ehavior and offers considerably more simulation flexibility than possi
ble with business simulators currently available. Suggestions for usin
g the new model to simulate real industries are provided.