|dc.description.abstract||"In an efficient market all identical goods must have only one price."
So states the aptly named law of one price. In the real world, however, one
may easily verify that identical products are often sold for different prices.
This thesis develops an extension of the Bertrand model in economics to
include spatially localised competition to explain this price variation, which
is then studied through simulation methods and theoretical analysis.
Our model studies the effect that local heterogeneities in the environment
experienced by sellers have on successful pricing strategies. Taking
inspiration from models of evolutionary dynamics, we define the fitness of
a seller and evolve seller prices through selection and mutation.
We find three distinct steady states in our model related to the probability
that a seller experiences competition for a buyer, mediated by the number
of bankrupt sites in the system. When competition-free sales are unlikely,
the system collapses on to a single price. If temporary monopoly situations
do exist sellers can accumulate capital and variation in prices is stable. In
this scenario, sellers spontaneously separate into two classes: cheap sellers
– requiring sales to every potential buyer; and expensive sellers – requiring
only occasional sales. Finally, we find an intermediate regime in which there
is a single highly favoured price in the system which oscillates between high
and low extrema.
We study the properties of these steady states in detail, building a picture
of how globally uncompetitive sellers can nonetheless survive if competition
is strictly local.We show how the system builds up correlations, leading to
niches for expensive sellers. These niches change the nature of the competition
and allow for long-term survival of uncompetitive sellers.
Not all expensive prices are equally likely in the steady state and we analyse
why (and where) peaks in the price distribution appear.We can do this
exactly for the early time dynamics of the model and extend the argument
more qualitatively to the steady state. This latter analysis allows us to predict,
for an observed steady distribution, the minimum price an expensive seller
should charge to guarantee profit.
The oscillatory ‘steady state’ is qualitatively reminiscent of boom and
bust cycles in the global market. We study methods to suppress the oscillations
and suggest ways of avoiding catastrophic crashes in the global
economy – without negatively affecting the ability of outliers to make large
|dc.publisher||The University of Edinburgh||en
|dc.relation.hasversion||L.Mitchell and G. J. Ackland. Strategy bifurcation and spatial inhomogeneity in a simple model of competing sellers. Europhysics Letters, 79(4):48003, 2007.||en
|dc.title||Competition in an evolving stochastic market||en
|dc.type||Thesis or Dissertation||en
|dc.type.qualificationname||PhD Doctor of Philosophy||en