In the Bertrand model of duopoly, each firm sets its price, believing that the other's price will not change.When both firms have identical production functions and produce with constant returns to scale, the Bertrand equilibrium price is equal to marginal cost.

Bertrand Model

An economic model that describes interactions between firms that compete by setting prices, assuming products are perfect substitutes.

Marginal Cost

The increase in cost that arises from producing one additional unit of a good or service, often considered for decision-making in production and pricing strategies.

Constant Returns

A situation in which increasing inputs in production results in a proportional increase in output.