Effects of Symmetry on Globalizing Separated monopolies to a Nash-Cournot oligopoly

The effects of uniting separated markets, each monopolized by a producer, into a globalized oligopolistic market, which is regarded as a non-cooperative game, are investigated. The cases where such globalization degrades the profits or surpluses of all producers, are examined. Linear demand and production functions are considered. The revenues of producers and consumers are assumed to be independent. It is shown that in complete symmetry, the degree of such degradation is highest, where the degree means the lowest of the degrees of the surplus degradation among all producers. The system is in complete symmetry when the values of parameters describing all producers and markets are identical. On the other hand, the degree of consumer surplus improvement is highest in some symmetry, where the degree means the lowest of the degrees of consumer surplus improvement among all (previously separated) markets. The system is in the symmetry when the values of parameters describing all producers are identical.