As this paper indicates: when only consider short-term effects and there are strongly differentiated products, the firms are motivated to merger.

Based on endogenous productivity, this paper studies differentiated products firms motives to carry out horizontal merger and the conditions of horiozntal merger.

This paper makes a study of the long run effect of differentiated products enterprises horizontal merger.

Author constructs a price war analysis model in oligarch competition market by the principle of micro economics and game theory, and two methods that can weaken the price war are proposed,one is union and merger,the another is to make product difference.

This paper employs a supergame model to indicate that product differentiation can increase cartel stability aiming at the intuition that product differentiation makes cartel maintaining more difficult.

The connotation of the core competence based on product differentiation is that the enterprise induces customers to prefer its products and chronically maintain their preference from forming horizontal product differentiation and vertical product differentiation.

Dorfman Steiner Rule points out that advertising intensity is determined by the own price and advertising elasticities of demand, but it doesn t further reveal the decisive factor of the two elasticities, that is product differentiation which further decides advertising intensity.