混合双寡头模型下的R&D竞争:不确定性和模仿视角

通过引入模仿参数δ来衡量R&D容易被模仿的程度,对Joanna Poya-go-Theotoky(1998)的研究进行了拓展,验证了其基本结论的稳健性。此外,通过引入二次R&D成本函数,研究发现,混合双寡头与私人双寡头情况下的社会福利的比较是不确定的,除了依赖创新规模P以外,还取决于模仿参数d,即——(1)对于任意的d,创新规模越大,私人双寡头越倾向于占优混合双寡头,混合双寡头仅在创新规模较小的时候可能优于私人双寡头;(2)对于创新规模比较小的R&D,只有同时具备较容易的模仿程度,混合双寡头才会优于私人双寡头;(3)在不完全模仿(d≠1)的情况下,在R&D越来越容易被模仿的过程中,利率越高(低),私人双寡头优于混合双寡头的最低P值先上升(下降)后下降(上升)。

R&D Competition under Mixed Duopoly:Perspectives of Uncertainty and Imitation

Using δ ’as parameter measuring R&D imitation,this paper extends Theotoky(1998)’s study and confirms the robustness of Theotoky’s conclusions.Besides,bringing in a quadratic R&D cost function,the paper suggests that depending on innovation size ‘P’ and imitation parameter ‘ δ ’,welfare comparing between mixed duopoly and private duopoly is ambiguous.That is,(1) for all d,the larger the innovation size is,the more possible private duopoly tends to dominate mixed duopoly,and only with lower P can mixed duopoly prevail;(2) for lower P,only together with higher d,can mixed duopoly prevail;(3) for d≠1,during δ ’s increasing process,the higher(lower) the interest rate is,the more possible the minimum value of P required for private duopoly’s dominance becomes larger(smaller) initially and then smaller(larger).