Publications
We present an inexact proximal point algorithm using quasi distances to solve a minimization problem in the Euclidean space. This algorithm is motivated by the proximal methods introduced by Attouch et al., section 4, (Math Program Ser A, 137: 91-129, 2013) and Solodov and Svaiter (Set Valued Anal 7:323-345, 1999). In contrast, in this paper we consider quasi distances, arbitrary (non necessary smooth) objective functions, scalar errors in each objective regularized approximation and vectorial errors on the residual of the regularized critical point, that is, we have an error on the optimality condition of the proximal subproblem at the new point. We obtain, under a coercivity assumption of the objective function, that all accumulation points of the sequence generated by the algorithm are critical points (minimizer points in the convex case) of the minimization problem. As an application we consider a human location problem: How to travel around the world and prepare the trip of a lifetime.
In this paper, we provide a better understanding of what drives sovereign wealth funds (SWFs) to improve their governance. Using the most recent SWF governance scoreboard from Maire et al. (2021), we estimate a fractional response model to determine whether SWF governance disclosure norms are driven by the search for internal or external legitimacy. Overall, we find that SWFs have better governance when they originate from democratic countries with high-quality, national governance. Our results also show that SWFs tend to have better governance quality when they need to acquire external legitimacy vis-à-vis the target company and its government. In particular, we find that SWFs have an incentive to improve their governance when they are sufficiently internationalized, when the amount of foreign assets invested abroad is sufficiently large or when the amount of shares acquired in developed countries is significant. These findings demonstrate how SWFs may proactively build legitimacy in host countries when they need to adapt their foreign entry strategies. Our results have important implications for understanding the determinants of SWF governance in general.
We study whether fiscal policies, especially public debt, can help to curb the macroeconomic and health consequences of epidemics. Our approach is based on three main features: we introduce the dynamics of epidemics in an overlapping generations model to take into account that old people are more vulnerable; people are more easily infected when pollution is high; public spending in health care and public debt can be used to tackle the effects of epidemics. We show that fiscal policies can promote convergence to a stable disease-free steady state. When public policies are not able to permanently eradicate the epidemic, public debt, and income transfers could reduce the number of infected people and increase capital and GDP per capita. As a prerequisite, pollution intensity should not be too high. Finally, we define a household subsidy policy that eliminates income and welfare inequalities between healthy and infected individuals.
In this paper, we develop an overlapping generations model with endogenous fertility and calibrate it to the Swedish historical data in order to estimate the economic cost of the 1918-19 influenza pandemic. The model identifies survivors from younger cohorts as main benefactors of the windfall bequests following the influenza mortality shock. We also show that the general equilibrium effects of the pandemic reveal themselves over the wage channel rather than the interest rate, fertility or labor supply channels. Finally, we demonstrate that the influenza mortality shock becomes persistent, driving the aggregate variables to lower steady states which costs the economy 1.819% of the output loss over the next century.
Over the years, oil prices and financial stock markets have always had a complex relationship. This paper analyzes the interactions and co-movements between the oil market (WTI crude oil) and two major stock markets in Europe and the US (the Euro Stoxx 50 and the SP500) for the period from 1990 to 2023. For that, I use both the time-varying and the Markov copula models. The latter one represents an extension of the former one, where the constant term of the dynamic dependence parameter is driven by a hidden two-state first-order Markov chain. It is also called the dynamic regime-switching (RS) copula model. To estimate the model, I use the inference function for margins (IFM) method together with Kim’s filter for the Markov switching process. The marginals of the returns are modeled by the GARCH and GAS models. Empirical results show that the RS copula model seems adequate to measure and evaluate the time-varying and non-linear dependence structure. Two persistent regimes of high and low dependency have been detected. There was a jump in the co-movements of both pairs during high regimes associated with instability and crises. In addition, the extreme dependence between crude oil and US/European stock markets is time-varying but also asymmetric, as indicated by the SJC copula. The correlation in the lower tail is higher than that in the upper. Hence, oil and stock returns are more closely joined and tend to co-move more closely together in bullish periods than in bearish periods. Finally, the dependence between WTI crude oil and the SP500 stock index seems to be more affected by exogenous shocks and instability than the oil and European stock markets.
We study a simple model in which two vertically differentiated firms compete in prices and mass advertising on an initially uninformed market. Consumers differ in their preference for quality. There is an upper bound on prices since consumers cannot spend more on the good than a fixed amount (say, their income). Depending on this income and on the ratio between the advertising cost and quality differential (relative advertising cost), either there is no equilibrium in pure strategies or there exists one of the following three types: (1) an interior equilibrium, where both firms have positive natural markets and charge prices lower than the consumer’s income; (2) a constrained interior equilibrium, where both firms have positive natural markets, and the high-quality firm charges the consumer’s income or (3) a corner equilibrium, where the low-quality firm has no natural market selling only to uninformed customers. We show that no corner equilibrium exists in which the high-quality firm would have a null natural market. At an equilibrium (whenever there exists one), the high-quality firm always advertises more, charges a higher price and makes a higher profit than the low-quality one. As the relative advertising cost goes to infinity, prices become equal and the advertising intensities converge to zero as well as the profits. Finally, the advertising intensities are, at least globally, increasing with the quality differential. Finally, in all cases, as the advertising parameter cost increases unboundedly, both prices converge increasingly towards the consumer’s income.
Objectives
We propose a general framework for estimating long-term health and economic effects that takes into account four time-related aspects. We apply it to a reduction in exposure to air pollution in the Canton of Geneva.
Study design
Methodological developments on the evaluation of long-term economic and health benefits, with an empirical illustration.
Methods
We propose a unified framework—the comprehensive impact assessment (CIA)—to assess the long-term effects of morbidity and mortality in health and economic terms. This framework takes full account of four time-related issues: cessation lag, policy/technical implementation timeframe, discounting and time horizon. We compare its results with those obtained from standard quantitative health impact assessment (QHIA) in an empirical illustration involving air pollution reduction in the canton of Geneva.
Results
We find that by neglecting time issues, the QHIA estimates greater health and economic benefits than the CIA. The overestimation is about 50% under reasonable assumptions and increases ceteris paribus with the magnitude of the cessation lag and the discount factor. It decreases both with the time horizon and with the implementation timeframe.
Conclusion
A proper evaluation of long-term health and economic effects is an important issue when they are to be used in cost-benefit analyses, particularly for mortality, which often represents the largest fraction. We recommend using the CIA to calculate more accurate values.
How will structural change unfold beyond the rise of services? Motivated by the observed dynamics within the service sector we propose a model of structural change in which productivity is endogenous and output is produced with two intermediate substitutable capital goods. In the productive sector the accumulation of specialized skills leads to an unbounded increase in TFP, as sector becoming asymptotically dominant. We are then able to recover the increasing shares of workers, the increasing real and nominal shares of the output observed in productive service and IT sectors in the US. Interestingly, the economy follows a growth path converging to a particular level of wealth that depends on the initial price of capital and knowledge. As a consequence, countries with the same fundamentals but lower initial wealth will be characterized by lower asymptotic wealth.
This paper examines the interaction between three financial markets: energy and non-energy commodities, bonds and equities, in a particular context of high inflation worldwide, that of Russia–Ukraine war. Our data cover the period January 2016-October 2022. Using a SETAR-GARCH C-Vine Copula model, we provide evidence of two inflation breakouts within COVID pandemic and shortly before Russia–Ukraine war, for all assets considered, and particularly for US 10-Year bond, as an inflation-indexed asset. Over the Russia–Ukraine war period, both linear and nonlinear models explain the studied assets’ behavior faced with high inflation. C-Vine Copula analysis shows that oil prices (WTI), as an inflation-producing assets, impact the volatility of financial markets (VIX) in times of war. This analysis indicates also that the NASDAQ index, as an inflation-exposed assets, is sensitive to commodities and energy prices that drive inflation. Furthermore, we find a high positive Kendall’s tau for all combinations between US 10-Year and all other assets. These results provide strong evidence of the association between US 10-Year futures, as a vehicle of inflation, and all studied assets. Lastly, our findings confirm the evidence that Russia–Ukraine war generated two significant shocks, Gas (NG) prices and financial markets’ volatility (VIX). This study is of crucial interest to policy and decision makers to the extent that it provides a framework for understanding, in a context of high inflation, the mechanisms linked to the vehicles for transmitting this inflation, its pricing process, and its impact on the equity market.
We study the behavioral determinants of COVID-19 vaccination uptake. The vaccine-pass policy, implemented in several countries in 2021, conditioned the access to leisure and consumption places to being vaccinated against COVID-19 and created an unprecedented situation where individuals’ access to consumption goods and vaccine status were interrelated. We rely on a quasi-hyperbolic discounting model to study the plausible relationships between time preference and the decision to vaccinate in such context. We test the predictions of our model using data collected from a representative sample of the French population (N = 1034) in August and September 2021. Respondents were asked about their COVID-19 vaccination status (zero, one, or two doses), as well as their economic and social preferences. Preference elicitations were undertaken online through incentivized tasks, with parallel collection of self-stated preferences. Factors associated with COVID-19 vaccination were investigated using a logistic model. Both elicited and stated impatience were found to be positively associated with COVID-19 vaccination decisions. These results suggest that impatience is a key motivational lever for vaccine uptake in a context where the vaccination decision is multidimensional and impacts the consumption potential. Results also serve to highlight the potential effectiveness of public communications campaigns based on time preferences to increase vaccination coverage.
