AN ELEMENTARY PROOF OF ARROW'S IMPOSSIBILITY THEOREM*

This paper deals with a situation where a quantity-setting Coumot firm and a price- setting Bertrand firm coexist in the same industry. Under a set of regularity conditions
on demand and cost, we compute equilibrium prices on Cournot-Bertrand "mixed" duopolies, and compare them with those of "pure"Cournot and Bertrand duopolies.