Under the price adjustment process only the prices of commodities having the highest excess demand are increased from their initial levels. Simultaneously, only the prices of commodities having the highest excess supply, i.e., lowest excess demand, are decreased from their initial levels. In this manner, the demand of a commodity with lowest excess demand is typically, but not necessarily, increased, while the demand for a commodity with highest excess demand is typically decreased. To ensure convergence of the price adjustment process, it is necessary to keep a price which has been raised or lowered from its starting level fixed at this initial level as soon as during the process that price becomes equal to its initial price again.