The aim of the paper is to investigate how the dual brand of firm decides its optimal allocation of advertising and fundamental strategy of marketing under taking account of markets with multi-consumption externalities. We assume that the market is multi-consumption externalities, and advertising may function as a device to coordinate consumer expectations of the purchasing decisions of other consumers, which is different from the past assumption that consumer type is single and role of advertising in market. Therefore, we reexamine the firm with optimal allocation of advertising. Finally, we show that the firm will adapt different pricing, allocation of advertising and strategy of marketing when facing the different consumer type of combination proportion. If market is dissimilar consumption externalities, above statement will be more significant; On the contrary, if firm facing similar consumption externalities, the optimal is single strategy. In other words, it is independent to consumer's type of combination proportion.

This paper is a combination of spatial duopoly model together with consumption externality model. Under the circumstance of heterogeneous products, I will discuss separately the influence of consumption externalities on the optimal equilibrium strategy of the firm. When consumers are characterized with the snob, the equilibrium price tends to be higher; however, consumers are characterized with the conformity, firms will be fierce price competition. Moreover, given the existence of conspicuous goods, consumers purchase a conspicuous good in order to display their relative high income and thereby achieve greater social status. And for this type of conspicuous consumers, the government will generally levy a luxury tax or even prohibit the consumption of the conspicuous good. And finally, by comparing these two cases with the laissez-faire economy, changes in the social welfare are exactly in an opposite direction.

This dissertation extends the Grossman-Helpman models of endogenous trade policy formation to incorporate local and global production and consumption externalities, and to allow governments to choose domestic production or consumption policies together with trade interventions. The models presented are among the first to allow environmental quality and the structure of industry protection to be simultaneously evaluated in a political economy framework, when some industry groups lobby their governments for higher output prices. The equilibrium tax and subsidy policies are implicitly expressed as the sum of distinct political support, terms-of-trade, and local and global environmental effects. Whether these effects reinforce or counterbalance each other depends on whether an industry is organized, whether the good is imported or exported, whether the externality is caused by production or consumption, and, in the large-country models, on whether governments set policies noncooperatively or cooperatively. The model results imply a political economy version of Bhagwati's normative targeting principle: governments use the most efficient policy available to satisfy the lobbies, to address the externalities, and, in the noncooperative large-country model, to exploit international market power. All of the initial Grossman-Helpman results (for the small-country model and the noncooperative and cooperative large-country models) are shown to be special cases where governments have only trade policy available and there are no externalities. In the small-country model and the cooperative large-country model, when there are production externalities, the lobbying of a polluting industry usually leads to lower environmental quality than socially optimal, but with terms-of-trade effects or for particular preferences cases the equilibrium policies may induce environmental quality higher than socially optimal. When there are consumption externalities, and the government has consumption (or production) as well as trade policy available, environmental quality will be socially optimal (again, unless governments exploit market power). Thus, depending on the policies available, a local or global consumption externality will be fully internalized, even though polluting industries lobby and production may be distorted. This dissertation also shows that--in contrast to standard economic theory--the use of trade policy alone can lead to higher environmental quality than a more direct domestic policy alone. / Ph. D.

許多策略性環境政策的相關文獻，大多在探討生產外部性的問題，較少著墨在消費的外部性，且在模型設定上，大多假設廠商生產同質性商品，因此本文將商品之差異性納入考量，在單邊貿易模型之下，建立一個兩階段賽局，來探討消費外部性的情況下，廠商與政府的策略性行為。而本文亦將貿易政策與環境政策做連結，探討當關稅因貿易自由化而調降時，對環境政策與環境品質的影響為何。 本研究發現：(1) 不論廠商的競爭型態為何，政府會將最適污染稅稅率訂在低於污染所造成的邊際環境損害之水準。(2) 不論廠商的競爭型態為何，貿易自由化會提升最適污染稅稅率。(3) 在廠商進行 Cournot 競爭時，貿易自由化將提升環境品質。(4) 在廠商進行 Bertrand 競爭時，關稅調降與否，須考量商品間的替代程度，在商品替代程度很低時，貿易自由化的結果將使環境品質向下沉淪。 / This thesis develops a two-stage game to investigate the strategies of government and firms concerning negative externalities associated with consumption. It also discusses the linkages between trade liberalization and environmental policy, namely, the effect of tariff reduction due to trade liberalization on environmental policy and environmental quality. Most of the literature on strategic environmental policy only considers negative externalities associated with production, but this thesis deals with negative externalities associated with consumption. Several conclusions emerge: First, the optimal pollution tax is less than the marginal pollution damage. Second, the environmental tax increases as a consequence of a tariff reduction. Third, if firms compete in terms of quantity, environmental quality could be improved by liberalizing trade. Finally, if firms compete in terms of price, when the degree of goods substitutability is low, trade liberalization may lead to a “race to the bottom” in environmental quality.

Phan (2003)等人的研究首先採用網路結構的觀點，來進行在獨占市場下的消費行為分析。本文延伸Phan等人的研究，採用多樣性的不同網路結構，特別是以「無標度網路」(scale-free)作為市場背後的網路結構，藉此來探討網路對於市場需求行為的影響。同時，為了有效地進行量化分析，我們建立了一些數學公式，以便能夠精準地比較不同網路對於需求面的影響程度，其中包含了消費者剩餘、雪崩效果和磁滯效果等。在實驗結果中，我們發現網路結構的確會影響到消費行為的表現，並且當市場規模變大時，仍存在著一些因網路不同而有的差異性。 / The economic implications of network topologies are studied via a monopolist's model of market networks originally proposed by Phan, et al. (2003). By embedding the market into a larger collection of network topologies, in particular, a class of scale-free networks, we extend the early analysis built upon a class of ring networks. To facilitate the study of the impacts of network topologies upon market demand, various measures concerning social welfare (the consumer's surplus), the avalanche effect, and the hysteresis effect, are formally established. Comparisons based on these measures show that network topologies matter, and their implied differences will remain even when the network size becomes large.

本文將貿易政策與環境政策做連結, 建構一雙邊貿易之架構, 設立一三階段之序列賽局,以之探討: 當具有跨國性質之消費性污染存在時, 在考量兩國政府皆有誘因在環境政策上採取非合作的態度下, 兩國政府應如何藉由貿易政策之協定, 訂定其最適之出口品補貼政策, 以矯正環境政策非合作下之不效率。 本文研究發現: 在兩國政府僅能夠進行政策的部分合作時, 當需求參數愈大, 兩國政府之最適貿易政策是應將給予其各自國家出口品之單位補貼調升;但若伴隨消費財貨所排放之污染對環境具有較高之邊際污染, 或是其本身之外溢效果愈強, 兩國政府對出口品之最適補貼則應該調降。我們同時也發現, 此時即使各國政府之最適貿易政策是調降出口補貼, 會使得各國之污染稅稅率更低, 但卻不會使其更加偏離兩國政府在環境政策上合作下之最適稅率, 並且仍會為全球帶來更高之社會福利。 / This paper constructs a reciprocal-market model, which contains a three-stage game to investigate how the two countries decide the optimal export subsidy agreement when they do not coordinate their environmental policy. We find that the level of optimal export subsidy should decrease with the strength of transboundary pollution, which is associated to consumption activities. In addition, the export subsidy agreement should increase with the demand parameter. We also find that even a reduction in the export subsidy will decrease the non-coordinated environmental tax rate, it will not deviate the tax rate away from the coordinated one and still enhance the social welfare.