existence of equilibrium and comparative statics in differentiated goods cournot oligopolies abstract we show that under horizontal differentiation pure symmetric cournot equilibria exist if firms react to a rise in competitors output in such a way that their market price does not rise this condition is related to strategic complementarity but not to convexity or differentiability we rule out multiple equilibria under some additional conditions and discuss stability and regularity of equilibria with ordinal methods following entry equilibrium price decreases only if competitors outputs enter inverse demand aggregated into a single number otherwise it may increase even in stable equilibria the comparative statics of quantities and profits for all equilibria are given

cournot oligopoly and the theory of supermodular games abstract we reconsider the cournot oligopoly problem in light of the theory of supermodular games invoking the recent ordinal version of this theory proposed by milgrom and shannon we generalize novshek s existence result derive the associated uniqueness result give an extension of a classical existence result under symmetry and provide conditions making a cournot oligopoly into a log supermodular game with the natural order on the action sets we also provide extensive and precise insight as to why decreasing best responses are widely regarded as being typical for the cournot model with production costs several illustrative examples are provided journal of economic literatureclassification numbers c72 l10 l13

urban concentration and agglomeration economies re examining the relationship using a sample of 49 countries and two stage least squares estimators the effects of urban concentration on economic growth are examined evidence is provided that external agglomeration economies in the largest cities have been exhausted although the process of concentration continues to have a positive impact on output this effect however is attributed to internal adjustments caused by concentration in factor intensity and marginal factor productivity in the production activities of urban areas the results suggest that a meaningful policy aiming to alleviate the social costs of concentration in over populated metropolises without reducing the overall efficiency of the economy should follow a long term strategy of developing smaller cities in the periphery and favouring the operation of smaller scale less capital intensive enterprises in the economy

what does an oligopoly maximize a monopolist maximizes a well defined objective function monetary profit in a competitive industry although each individual pursues selfish objectives the market behaves as if an agent was maximizing an objective function social welfare can we say the same for an oligopoly do firms pursuing selfish objectives and behaving strategically act as if an agent was maximizing a fictitious objective function necessary and sufficient conditions for nash equilibria of static and state space games to be observationally equivalent to single optimization problems are derived nash equilibria of the game that are not maxima of the function are shown to be generically unstable copyright 1994 by blackwell publishing ltd

determinants of health care expenditure in africa a cross sectional study the paper presents some quantitative evidence on the relationship between certain socioeconomic and demographic factors and per capita health care expenditure in africa first gnp per capita percentage of births attended by health staff and foreign aid received per capita together explained 78 3 of the variance in health care expenditure second per capita gnp is the most significant factor explaining differences in health care expenditure contrary to what has been found in comparisons of health care expenditure in the organization for economic cooperation and development oecd countries we found that the income elasticity is close to unity furthermore aid was consistently significant and positive in the three models estimated third variables such as crude birth rate and the population under 15 years of age as percentage of total population were not significant

aggregate health care expenditure in the united states evidence from cointegration tests unlike recent studies that are based on international cross sectional series this paper attempts to quantify the role of the determinants of aggregate health care expenditure per capita using time series data for the period of 1960 87 for the united states the paper applies the relatively new procedures of unit root testing cointegration and error correction modelling the evidence supports cointegration although the results indicate that per capita income age of the population number of practising physicians and public financing of health care are important determinants the age structure of the population and number of practising physicians emerge as the major determinants of aggregate health care expenditure in the united states

aggregate health care expenditures and national income is health care a luxury good it is well known that a strong relationship exists between national expenditures on health care and national income this has been used to suggest that health care is a luxury good and that factors such as the type of health care delivery system in a country are of little importance in determining expenditure levels this paper argues that these implications rely upon the application of microeconomic analysis to macroeconomic data and that this is not appropriate as well as raising questions about the inferences drawn from previous studies new empirical evidence is presented which casts some doubts on previous findings international comparisons are based on purchasing power parity rather than exchange rate conversions underlining the importance of prices as well as quantities in the relationship and leading to the conclusion that the aggregate data show health care to be if anything a necessity rather than a luxury good

contributions to cournot oligopoly theory abstract this work contributes to a number of questions concerning oligopoly models in particular uniqueness of the cournot equilibrium point is demonstrated under the assumption that either the unit price function is differentiable and the derivative is strictly negative or the cost functions are strictly convex also under the assumption of either strictly decreasing unit price function or strictly convex cost functions it is shown that a the total production level at equilibrium increases with entry of additional players b that cooperation between some of the players necessarily entails profit for the others and c cooperative grouping causes decrease in production levels

the existence of equilibrium in discontinuous economic games i theory the article presents information about the existence of equilibrium in discontinuous economic games in this paper and its sequel presents study the existence of nash equilibrium in games where agents payoff functions are discontinuous the enquiry is motivated by a number of recent studies that have uncovered serious existence problems in seemingly innocuous economic games in the sequel to this paper authors have explained the utility function in the economic games referred to earlier are neither continuous nor quasi concave however they demonstrate that the payoff functions in mildly modified versions of these constructs exhibit two weaker forms of continuity which together with the requirement of quasi concavity suffice for the existence of an equilibrium from this one may conclude that at least in the modified versions of these models discontinuities in the payoff functions are not the real source of the problem rather it is the failure of the payoff functions to the quasi concave which is responsible for the non existence of equilibrium these observations bear on the existence of nash equilibrium in pure strategies

evidence on the determinants of canadian provincial government health expenditures 1965 1991 abstract real per capita provincial government expenditures on health care over the period 1965 1991 are examined using pooled time series cross section regression analysis key determinants of real per capita provincial government expenditures on health care over the period 1965 1991 are real provincial per capita income the proportion of the provincial population over age 65 and real provincial per capita federal transfer revenues established program financing had a negative and significant impact on real per capita provincial government health expenditures in newfoundland and quebec an income elasticity of 0 77 implies that health care is not a luxury good

the stability of the cournot oligopoly model a reassessment abstract the stability properties of the cournot oligopoly model are examined for the continuous adjustment process sufficient conditions for instability are established which are shown to be of significance when the number of firms n is small local and global stability are shown under appropriate conditions which for global stability include the restriction n 5 the proof of global stability corrects a well known proof by f hahn rev econ stud 29 1962 329 331 results for the discrete time adjustment process are reported and the restrictiveness of the model s assumptions are discussed

an econometric analysis of health care expenditure a cross section study of the oecd countries this paper is an empirical examination of the determinants of aggregate health care expenditure the paper presents a systematic analysis of relationships across 19 oecd countries showing the effects of aggregate income institutional and socio demographic factors on health care expenditure the results indicate that institutional factors of the health systems in addition to per capita gross domestic product gdp contribute significantly to the explanation of the health care expenditure variation between countries for example the way physicians in outpatient care are paid and the mixture of public private funding and inpatient outpatient care

is a unique cournot equilibrium locally stable abstract we consider a homogeneous product oligopoly where the cournot equilibrium is regular and unique we show that for a duopoly a unique cournot equilibrium is always locally stable for a n firm asymmetric cost oligopoly a unique cournot equilibrium is locally stable under very general conditions the sufficient conditions for local stability of a unique cournot equilibrium are much less restrictive than what the existing literature suggests for a symmetric cost oligopoly the unique cournot equilibrium is almost always locally stable except for a perverse case journal of economic literature classification number l13

supermodularity and complementarity in economics an elementary survey the literature on supermodular optimization and games is surveyed from the perspective of potential users in economics this methodology provides a new approach for comparative statics based only on critical assumptions and allows a general analysis of games with strategic complementarities the results are presented in a simplified yet rigourous manner without reference to lattice theory for the special case of one dimensional parameter and actions sets with the emphasis being on wide accessibility detailed applications are presented for well known models of consumer behavior monopoly pass through bertrand and cournot competition strategic r d search and matching wherever appropriate useful tricks for applications and comparative comments are inserted

network effects market structure and industry performance abstract this paper analyzes oligopolistic markets with network externalities exploiting a minimal complementarity structure on the model primitives that allows for pure network goods we prove existence of non trivial fulfilled expectations equilibrium we formalize the concept of industry viability investigate its determinants and show that it improves with more firms in the market and or by technological progress these results enlighten some well known conclusions from case studies in the management strategy literature we also characterize the effects of market structure on industry performance which depart substantially from ordinary markets the approach relies on lattice theoretic methods supplemented with basic insights from nonsmooth analysis

lechatelier samuelson principle in games and pass through of shocks abstract the lechatelier samuelson principle states that as a reaction to a shock an agent s short run adjustment of an affected action is smaller than its long run adjustment when the agent can also adjust other related actions we extend the principle to strategic environments where the long run adjustment also accounts for other players adjusting their strategies we show that the principle holds for supermodular games strategic complements satisfying monotone comparative statics and provide sufficient conditions for the principle to hold in games of strategic substitutes heterogeneity we discuss the principle s implications for cost pass through of multiproduct firms

the determinants and effects of health expenditure in developed countries previous studies of international differences in health spending have been restricted to the use of relatively small samples of cross sectional data our objective here is to re examine the results of previous work using a sample of 560 pooled time series and cross section observations results confirm the importance of gdp as a determinant of health spending with an estimated income elasticity at or around unity but also suggest that oecd countries should not be regarded as a single homogeneous group the importance of some non income variables is also confirmed although the direct effect of these factors appears to be small

on the effects of entry in cournot markets in the framework of symmetric cournot oligopoly this paper provides two minimal sets of assumptions on the demand and cost functions that imply respectively that as the number of firms increases the minimal and maximal equilibria lead to i decreasing industry price and increasing or decreasing per firm output and ii increasing industry price and decreasing per firm output in both cases per firm profits are decreasing the analysis relies crucially on lattice theoretic methods and yields general unambiguous and easily interpretable conclusions of a global nature as a byproduct of independent interest new insight into existence of cournot equilibrium is developed

cointegration and dynamic time series models abstract this paper provides a survey of some of the recent developments in the field of econometric modelling with cointegrated time series in particular we describe the testing and estimation procedures which have become increasingly popular in the recent applied literature in addition to the two stage procedure proposed by engle and granger we consider extensions to the modelling of dynamic models with cointegrated variables such as the estimation of models with multiple cointegration vectors simultaneous systems models with seasonally integrated and cointegrated variables furthermore we illustrate the practical application of the techniques describes in the paper by means of a tutorial data set

rationalizability learning and equilibrium in games with strategic complementarities we study a rich class of noncooperative games that includes models of oligopoly competition macroeconomic coordination failures arms races bank runs technology adoption and diffusion r d competition pretrial bargaining coordination in teams and many others for all these games the sets of pure strategy nash equilibria correlated equilibria and rationalizable strategies have identical bounds also for a class of models of dynamic adaptive choice behavior that encompasses both best response dynamics and bayesian learning the players choices lie eventually within the same bounds these bounds are shown to vary monotonically with certain exogenous parameters we study the class of noncooperative supermodular games introduced by topkis 1979 and further analyzed by vives 1985 1989 who also pointed out the importance of these games in industrial economics supermodular games are games in which each player s strategy set is partially ordered the marginal returns to increasing one s strategy rise with increases in the competitors strategies so that the game exhibits strategic complementarity 2 and if a player s strategies are multidimensional marginal returns to any one com ponent of the player s strategy rise with increases in the other components this class turns out to encompass many of the most important economic applications of noncooperative game theory in macroeconomics diamond s 1982 search model and bryant s 1983 1984 rational expectations models can be represented as supermodular games in each of these models more activity by some members of the economy raises the returns to increased levels of activity by others in oligopoly theory some models of bertrand oligopoly with differentiated products qualify as supermodu lar games in these games when a firm s competitors raise their prices the marginal profitability of the firm s own price increase rises a similar structure is present in games of new technology adoption such as those of dybvig and spatt 1983 farrell and saloner 1986 and katz and shapiro 1986 when more users hook into a communication system or more manufacturers adopt an interface standard the marginal return to others of doing the same often rises similarly in some specifications of the bank runs model introduced by diamond and dybvig 1983 when more depositors withdraw their funds from a bank it is more worthwhile for other depositors to do the same in the warrant exercise

on the existence of cournot equilibrium this paper examines the existence of n firm cournot equilibrium in a market for a single homogeneous commodity it proves that if each firm s marginal revenue declines as the aggregate output of other firms increases which is implied by concave inverse demand then a cournot equilibrium exists without assuming that firms have nondecreasing marginal cost or identical technologies also if the marginal revenue condition fails at a potential optimal point there is a set of firms such that no cournot equilibrium exists the paper also contains an example of nonexistence with two nonidentical firms each with constant returns to scale production