十字型市場的空間差別定價——Bertrand 與 Cournot

Spatial discrimination in a cross-street market: Bertrand VS. Cournot

本文在十字型市場的空間型態下，研究廠商的空間差別定價及區位競爭，我們同時討論生產同質產品的雙占廠商，做Bertrand的價格競爭與Cournot的數量競爭。研究結果發現，在Bertrand競爭之下，不存在對稱的區位均衡，而一家廠商坐落在十字型市場的中心點，另一家廠商與其區位分離，是唯一的區位均衡。在Cournot競爭之下，雙占廠商區位聚集在十字型市場的中心點是唯一的+R43區位均衡。在福利分析方面，研究發現，Cournot競爭之下的消費者剩餘、產業利潤與社會福利，皆高於Bertrand競爭之下的消費者剩餘、產業利潤與社會福利，此結果隱含，此十字型市場的空間競爭模型，可以解決傳統非空間模型中，消費者、廠商與政府（社會規劃者）之間的誘因不一致問題。

We investigate the theory of spatial discrimination in a cross-street market and discuss two types of market competition-Bertrand and Cournot-with homogeneous goods and endogenous location choices. The result is that asymmetric dispersion, where one firm locates at the market center while the other firm locates in the interior, is the unique location equilibrium under Bertrand competition. Duopoly firms choose to agglomerate at the market center under Cournot competition. We also find that consumer surplus, industry profits, and social welfare are all higher under Cournot competition than under Bertrand competition. This implies that introducing a spatial barrier to competition generated through transportation costs may solve the problem of inconsistency from the conflicting interests among consumers, firms, and a social planner.