Locally lipschitz cooperative games

A locally Lipschitz cooperative generalized game is described by its coalition worth function v defined on the set [0, 1]ⁿ of generalized (or fuzzy) coalitions of n players. We assume that v is positively homogeneous and locally Lipschitz. We propose the Clarke's generalized gradient ∂v(c^N) of v at the coalition c^N=(1,…,1) of all players as a set of solutions, and we study its property. We point out that it coincides with the core when v is super–additive and to the Shapley value when v is smooth.     

On the impact of shock persistence on the dynamics of a recursive economy

The present note relies exclusively on numerical computation of a parametric version of a (stochastic) version of the one-sector neoclassical growth model to derive the qualitative properties of the optimal consumption/investment policy functions and of the resultant steady state, and to study the manner in which these properties are affected by an increase in the degree of shock persistence. In particular, we measure the effects of (differing degrees of) shock persistence on the means and variances of the resulting (stationary) distributions on output, consumption, and capital stock. Furthermore, we explore the effects of increasing degrees of shock persistence on the dynamic time path of the economy.     

Asymmetries in cost structures and incentives towards price competition

This paper provides some theoretical grounds to relate asymmetries in cost structures and incentives towards price competition. Typically low cost firms favor price competition whereas the reserve is true for high cost firms. Increased price competition will tend to diminish price-cost margins for all firms but the low cost firms may increase their total profits through an enlarged market share. This analysis depends on two relevant parameters: the way the overall market will react to increased price competition and interfirm cross elasticities. This is proved using comparative statics at the Nash equilibrium of an oligopolistic model.     

Information revelation in auctions

Auction theory has emphasized the importance of private information to the profits of bidders. However, the theory has failed to consider to what extent initially private information will remain private. We show that in a variety of contexts bidders will reveal their information, even if this information revelation is (ex ante) detrimental to them. Similarly, a seller may reveal her information although this revelation lowers revenues. We also show that bidders may be harmed by private information, even in contexts where more information has traditionally been presumed to be beneficial.     

On Intersectoral allocations,factors substitutability and multiple long-run growth paths

Summary. This article considers a two-sector model of economic growth with “labour-augmenting” intersectoral external effects stemming from the aggregate capital stock. It is shown that equilibrium balanced growth paths with a non-trivial labour allocation scheme become available. A set of sufficient conditions for the existence of multiple equilibrium growth rays is provided and their determinacy properties are then characterised. Finally, examination of a parameterised C.E.S. economy illustrates the central role of non-unitary values for the elasticity of substitution in the multiplicity issue. Received: October 31, 2000; revised version: September 25, 2001     

‘Fit to play’: Labour market behaviour in a cohort of public-sector antiretroviral treatment patients

Given the rapid scale-up of antiretroviral treatment (ART), it is necessary to explore the impact of ART on labour force participation, employment and labour productivity. This article investigates labour market outcomes in a prospective cohort of public-sector ART clients in the Free State province of South Africa. Empirical results suggest that labour force participation increased markedly as the proportion of those too ill to work declined, becoming indistinguishable from participation rates in the general population. Unemployment rates, however, remain above those reported for the general population. ART and its health-related benefits therefore translate into increases in labour force participation, but not employment. Employment status at HIV diagnosis strongly predicts absorption in the labour force. Public-sector ART clients should be referred to vocational rehabilitation and occupational therapy programmes, and to welfare-to-work programmes, and the unskilled to adult education and training and further education and training programmes.     

The spatial demography of new plants: urban creation and rural survival

This study shows that the survival rate of new plants depends on their spatial location. A panel dataset of French plants, observed between 1993 and 2002, provides annual samples of more than 300,000 new plants, each plant being defined as rural, peri-urban, urban or located in the Paris region. A survival model is developed, introducing the location variable alongside the usual survival determinants, such as size, industry and period. Estimation results clearly show that it is easier to create a new plant in urban areas, particularly in the Paris region, but less difficult to survive in rural ones. Agglomeration forces may explain the first result, and the intensity of local competition variable, the second. However, even once the local competition effect is controlled, rural new plants still exhibit significantly higher survival rates. The entrepreneurial theory of opportunity may help to understand such a result. The density of population, activities and information offer more opportunities to start an activity, but also to quit it once it has been created.     

RAINFALL, THE MÉLINE TARIFF, AND WHEAT PRODUCTION IN MEDITERRANEAN FRANCE, 1885–1914

Wheat production stagnated in France during the late nineteenth and early twentieth century, while cultivated acreage and wheat output declined sharply around the Mediterranean from the 1870s. Wheat output never recovered in this region despite the introduction in 1885 of tariff measures, such as the 1892 Méline Tariff. This paper analyses the response of Mediterranean wheat growers to changes in local rainfall and to variations of the duty on imported grains. It uses regional level data for nine administrative divisions located on or near the Mediterranean and assesses the impact of rainfall on yields. It argues that an interplay of protectionist policies and environmental conditions explain the decline of wheat production.     

Nonparametric estimation of an instrumental regression: A quasi-Bayesian approach based on regularized posterior

We propose a quasi-Bayesian nonparametric approach to estimating the structural relationship φ$\phi$ among endogenous variables when instruments are available. We show that the posterior distribution of φ$\phi$ is inconsistent in the frequentist sense. We interpret this fact as the ill-posedness of the Bayesian inverse problem defined by the relation that characterizes the structural function φ$\phi$. To solve this problem, we construct a regularized posterior distribution, based on a Tikhonov regularization of the inverse of the marginal variance of the sample, which is justified by a penalized projection argument. This regularized posterior distribution is consistent in the frequentist sense and its mean can be interpreted as the mean of the exact posterior distribution resulting from a Gaussian prior distribution with a shrinking covariance operator.