Optimal emission-extraction policy in a world of scarcity and irreversibility

This paper extends the classical exhaustible-resource/stock-pollution model with irreversibility of pollution decay, meaning that after reaching some threshold there is no decay of the pollution stock. Within this framework, we answer the question how the potential irreversibility of pollution affects the extraction path. We investigate the conditions under which the economy will optimally adopt a reversible policy, and when it is optimal to enter the irreversible region. In the case of irreversibility it may be optimal to leave a positive amount of resource in the ground forever. As far as the optimal extraction/emission policy is concerned, several types of solutions may arise, including solutions where the economy stays at the threshold for a while. Given that different programs may satisfy the first order conditions for optimality, we further investigate when each of these is optimal. We show that it is never optimal for the economy to stay at the threshold for a while before entering the irreversible region. The optimality analysis is then illustrated by means of a calibrated example. To sum up, for any pollution level, we can identify a critical resource stock such that there exist multiple optima i.e. a reversible and an irreversible policy that yield exactly the same present value. For any resource stock below this critical value, the optimal policy is reversible whereas with large enough resources, irreversible policies outperform reversible programs.     

Optimal tariffs,optimal taxes and economic development

Cross-section and time-series data suggest that nations substitute income taxes for tariffs as they develop. This paper confronts the data within the context of a two-country open-economy endogenous growth model in which public expenditure is financed by an optimal tariff and income tax. When the latter is subject to administrative costs, the model predicts that the government will optimally substitute the income tax for the tariff as output rises along the transition. The model is calibrated and a simulation yields time paths for the shares of total government revenue derived from the tariff and the income tax that are consistent with the data.     

Non-convex optimal portfolio sets and constant relative risk aversion

This paper shows by example that, under constant relative risk aversion (CRRA), the set of optimal portfolios can be non-convex even in the presence of a complete set of Arrow-Debreu securities. This implies that, with exclusively CRRA investors, market models without a strong distributional assumption such as that of the capital asset pricing model cannot be tested by testing the optimality of the market portfolio, or by assuming a representative investor. This demonstration extends the key result of Dybvig and Ross [Dybvig, P. H., & Ross S. A. (1982). Portfolio efficient sets. Econometrica, 50, 1525–1546], who showed an example of non-convexity with less restrictive utility assumptions but which could not apply to the case of a complete set of Arrow-Debreu securities.     

双重委托代理理论与股权集中型公司治理最优化研究综述

基于双重委托代理理论模型构建的股权集中型公司治理最优化研究,试图基于双重委托代理理论模型的构建而确立一种股权集中型公司治理问题的一般分析框架,希冀解析基于一定公司治理环境及其变迁的公司治理最优化特别是股权集中型公司治理最优化这一问题的理论涵义与实践要旨,其对于丰富公司治理理论与促进公司治理实践的重要意义不言而喻.本文由此出发,对既有相关研究进行了述评,并有基于此,就基于双重委托代理理论模型构建的股权集中型公司治理最优化研究的主要内容与关键问题进行了阐述.     

Disability insurance and optimal income taxation

This paper studies the design of disability insurance scheme when agents differ in their privately known productivity. We extend the Diamond and Mirrlees (1978) two period model to allow for agents differing ex-ante in their productivity and characterize the optimal nonlinear tax transfer that maximizes a utilitarian welfare function when per-period earnings and age are observable while individuals’ productivity and health status are not observable. We show that the induced tax/benefit scheme should exhibit a marginal income tax that decreases with age for some agents. A marginal subsidy on the young high productive income may be desirable. While the disability scheme always involves the old low productive agents to be indifferent between working and claiming disability benefits, this result is not always true for the old high productive agents. JEL Classification H55 · H23 · E62     

Monetary Policy with Uncertain Parameters

This paper shows that—in contrast to the received wisdom—uncertainty about the parameters in a dynamic macroeconomic model may lead to more aggressive monetary policy. In particular, when there is uncertainty about the persistence of inflation, it may be optimal for the central bank to respond to shocks more aggressively in order to reduce uncertainty about the future development of inflation. Uncertainty about other parameters, on the other hand, dampens the policy response.
JEL classification : E 43; E 52     

Optimal designs for a mixed interference model

This paper generalizes Kunert and Martin’s (Ann Stat 28:1728–1742, 2000) method for finding optimal designs under a fixed interference model, to find optimal designs under a mixed interference model. The results are based on the properties of information matrices in fixed and mixed models given in Markiewicz (J Stat Plan Inference 59:127–137, 1997). The method is applied to find a design which is optimal for any given variances of random neighbor effects. Research partially supported by the KBN Grant Number 5 P03A 041 21.     

Optimal designs for generalized linear models with biased response

This paper is concerned with the search for locally optimal designs when the observations of the response variable arise from a weighted distribution in the exponential family. Locally optimal designs are derived for regression models in which the response follows a weighted version of Normal, Gamma, Inverse Gaussian, Poisson or Binomial distributions. Some conditions are given under which the optimal designs for the weighted and original (non-weighted) distributions are the same. An efficiency study is performed to find out the behavior of the D-optimal designs for the original distribution when they are used to estimate models with weighted distributions.     

The Minimal Entropy Martingale Measures for Exponential Additive Processes

In this paper, we will consider exponential additive processes as a financial market model. Under a mild condition, we will determine the minimal entropy martingale measures (MEMMs) for the exponential additive processes. To this end, we will prepare several results on the exponential moment of additive processes and integrals based on them. As an application of our result, we will deduce optimal strategy for exponential utility maximization problem. We will also investigate our result through several examples, such as time-dependent versions of double Poisson model, Merton model and Kou model.     

Ramsey policies in a small open economy with sticky prices and capital

This paper analyzes jointly optimal fiscal and monetary policies in a small open economy with capital and sticky prices. We allow for trade in consumption goods under perfect international risk-sharing. We consider balanced-budget fiscal policies where authorities use distortionary taxes on labor and capital together with monetary policy using the nominal interest rate. First, as long as a symmetric equilibrium is considered, the steady state in an open economy is isomorphic to that of a closed economy. Second, sticky prices’ allocations are almost indistinguishable from flexible prices allocations both in open and closed economies. Third, the open economy dimension delivers results that are qualitatively similar to those of a closed economy but with significant quantitative changes. Tax rates are both more volatile and more persistent to undo the distortions implied by terms of trade fluctuations.