Differentiated Bertrand competition is an economics theory. As a solution to the Bertrand paradox in economics, it has been suggested that each firm produces a somewhat differentiated product, and consequently faces a demand curve that is downward-sloping for all levels of the firm's price. An increase in a competitor's price is represented as an increase (for example, an upward shift) of the firm's demand curve. As a result, when a competitor raises price, generally a firm can also raise its own price and increase its profits.
Calculating the differentiated Bertrand model q1 = firm 1's demand, *q1≥0 q2 = firm 2's demand, *q1≥0 A1 = Constant in equation for firm 1's demand A2 = Constant in equation for firm 2's demand a1 = slope coefficient for firm 1's price a2 = slope coefficient for firm 2's price p1 = firm 1's price level pr unit p2 = firm 2's price level pr unit b1 = slope coefficient for how much firm 2's price affects firm 1's demand b2 = slope coefficient for how much firm 1's price affects firm 2's demand q1=A1-a1*p1+b1*p2 q2=A2-a2*p2+b2*p1
The above figure presents the best response functions of the firms, which are complements to each other.
Uses Merger simulation models ordinarily assume differentiated Bertrand competition within a market that includes the merging firms.
See also Bertrand competition Bertrand paradox (economics) Oligopoly theory
References
External links Oligoply Theory made Simple, Chapter 6 of Surfing Economics by Huw Dixon.