相較於其他文獻強調對稱性，本文允許廠商具有垂直差異，換言之，較有效率的廠商反應較高的正初利潤(Positive Primary Markup)，而較沒有效率的廠商其正初利潤為較低。其次，透過兩階段品質賽局，第一階段廠商進行產品研發，可以提高正初利潤
This dissertation concludes three parts related to research and development(R&D) in an asymmetric duopoly. We use a representative-consumer model where the demands arise from a representative consumer's quasi-linear utility function, and each demand function is linear. The firms are allowed to be asymmetric: If the initial primary markup of a firm is higher than that of its rival, then it (its rival) is referred to as the more (less) efficient firm. Throughout three topics, we obtain that (1) the presence of R&D investment makes it harder for the less efficient firm to survive
(2) the more efficient firm has a normal output ranking
(3) equilibrium represents three types: blockaded-entry, deterred-entry and accommodated-entry equilibrium. The other results are as follows:
Part I, we compare the Cournot and Bertrand equilibria in a two stage duopoly game where, in the first stage, the firms compete in product R&D. Cournot competition entails a unique equilibrium, whereas Bertrand competition may yield two equilibria. Under each mode of competition, it is easier for the less efficient firm to survive under Cournot than under Bertrand competition. Two crucial results are established regarding firm size. First, Bertrand competition yields higher industry output than does Cournot competition. Second, compared with Cournot competition, Bertrand competition shifts production from the less to the more efficient firm. These crucial results, together with the known size effect, explain the following three results. First, the more efficient firm has a normal output ranking, whereas the less efficient firm may demonstrate an output reversal. Second, the more efficient firm may demonstrate a R\&D reversal, whereas the less efficient firm has a normal R&D ranking (its Cournot R&D effort exceeds its Bertrand R&D effort). Third, Bertrand competition would be more welfare-efficient than Cournot competition. Moreover, the more efficient firm may demonstrate a price reversal, whereas the less efficient firm has a normal price ranking.
Part II, we concern a Cournot duopoly game with two stages-the R&D first stage and the product-competition second stage. We aim at characterizing a second-best policy in which the social planner can control the first stage through R&D subsidies but cannot regulate the second stage. It is easier for the less efficient firm to survive under Cournot competition than under Second-best. A more efficient firm produces more output(engages in more R&D activity) under Second-best than under Cournot competition, whereas the ranking of output and quality of a less efficient firm may reversal. When blockaded-entry strategy prevails, subsidization of efficient firm improves social welfare
whereas deterred-entry strategy prevails, subsidization can not achieve the socially second-best equilibrium. When accommodated-entry strategy prevails, subsidization of efficient firm always improves social welfare. However, subsidization or taxation of less efficient firm depends upon asymmetric degree.
Part III, we characterize the equilibria in a two stage mixed duopoly game where firms compete each other in the first stage of engagement in R&D activity and in the second stage of Cournot competition. The result demonstrates that public firm may engage in less R&D activities than private firm only if private firm is sufficiently efficient. Compared with private duopoly or mixed duopoly with an efficient private firm, mixed duopoly with an efficient public firm yields higher social welfare, which is correspondent to higher criteria, including total output, total R&D level, Herfindahl index. Under partial privatization of mixed duopoly with an efficient public firm, we find that those criteria decrease with increasing degree of partial privatization. With increasing efficiency of private firm, optimal degree of partial privatization increases and it may cause lower criteria compared to mixed duopoly with an efficient public firm.