Fixed Point Theorems And Nash Equilibrium In Tariff Models

This paper deepens the model of Yoshitomo Ogawa. We establish a tar-iffs model of two countries and each of them has one government and multi-company. There are multiple import and export commodities in the model. The first part of this paper provide the structural expression of optimal profit tariff rates. And the second part of this paper proofs the existence of the equilibri-um of the model by using Nash equilibrium existence theorem and fixed-point theorem. The last part of this paper we get necessary and sufficient condition of optimal gain when the tow countries implement unified tariff policy. And we also discuss extreme cases to the non uniform tariff policy in the last part of this paper.