This paper introduces costly product differentiation into a mixed duopoly with strategic location choice in the first stage and price competition in the second stage. Initially, both firms locate at the center with no product differentiation. We demonstrate that the location choices critically depend on the effectiveness of investments in creating product differentiation, and the nationality of the private firm. Firstly, firms choose to move toward the edge only when the investments are sufficiently effective, regardless of whether the private firm is domestic or foreign. Secondly, a profit-maximizing (domestic or foreign) private firm invests more than the public firm which maximizes social welfare. Thirdly, a mixed duopoly with a foreign firm generates a lower degree of product differentiation in comparison to that with a domestic private firm.

本文将成本高昂的产品差异化引入混合双头垄断，在第一阶段选择战略位置，在第二阶段进行价格竞争。最初，两家公司都位于中心，没有产品差异化。我们证明，地点的选择主要取决于投资在创造产品差异化方面的有效性以及私人公司的国籍。首先，企业只有在投资足够有效时才选择走向边缘，而不论私营企业是国内还是国外。其次，利润最大化（国内或国外）的私人公司的投资要比公共公司更多，从而使社会福利最大化。第三，与国内私人公司相比，与外国公司的混合双头垄断产生的产品差异程度较低。