A model of multiproduct price competition

We provide a simple model of price competition in a multiproduct oligopoly market. The products are of general nature. We find that a pure strategy equilibrium exists and every equilibrium consumption maximizes the total social surplus. Consumers are characterized by a set function which determines their willingness to pay for every subset of products. If this function is convex, the set of equilibrium prices coincides with the core of a cooperative game generated by this set function and the firms extract total industry surplus. If it is concave, the only equilibrium price of a product is its marginal contribution to the consumer's total willingness to pay. (C) 1997 Academic Press.