林业规模经济的非线性均衡分析研究

本文将林业规模经济分为两类,即林业经济效益的规模经济和林业三大效益的规模经济。在分析林业经济效益的规模经济时,引入了成本变量,简要说明了林业经营成本与林业经济效益成反向变动关系。在分析林业三大效益的规模经济问题时,运用非线性均衡分析方法,并通过建立模型论证了林业三大效益达到最大化即均衡状态时所必需的条件。对林业三大效益规模经济问题的分析是本文核心部分,旨在为林业三大效益均衡问题的研究提供若干参考依据,同时也为林业合作经济组织的发展提供指导。     

Strategic nonlinear pricing

The objective of this paper is to examine the role of nonlinear strategies in a standard oligopoly framework. We demonstrate that nonlinear pricing may indeed emerge as an equilibrium strategy, but only when firms produce differentiated products, when one firm retains market power due to a cost advantage, or as part of an equilibrium in mixed strategies. In addition, we examine the role of nonlinear pricing in a spatial-competition framework. Our main conclusion is that in highly competitive markets, nonlinear pricing strategies are not likely to emerge as an equilibrium.     

Re‐Examining the Role of Structural Change and Nonlinearities in a Phillips Curve Model for South Africa

Although studies generally find evidence of a Phillips curve‐type relationship in South Africa, uncertainty remains about the relevance of the model over a relatively long sample period, and whether conventional output gap measures are suitable proxies for demand pressure. This paper reviews research which shows that the Phillips curve model prevails over an extended sample, provided that the benchmark specifications include major structural changes in the balance‐of‐payments and labour market, and account for shifts in the root causes of inflation. When this is done, a linear specification with an output gap in levels correctly predicts the non‐trended inflation pattern over the period 1971(Q1)–1984(Q4), whereas a piecewise concave curve with an output gap in growth rates accurately forecasts the decelerating inflation pattern during 1986(Q1)–2001(Q2). A novel feature of the concave model is that it remains statistically robust and structurally stable when it is estimated until 2015(Q4). The concave model imparts a disinflationary bias, which suggests that monetary policy should be more expansionary during downswing phases of the business cycle and neutral during upswing phases. The analysis also considers how the shape of the Phillips curve might change if the balance‐of‐payments constraint on demand is relaxed in a significant way.     

Exports and economic growth in Sub-Saharan Africa: New insights from innovative econometric methods

This study examined the relationship between exports and economic growth in Sub-Saharan Africa. It employed innovative econometric methods, including the Fourier ADF with structural break test, a comparative analysis of three causality tests and a rolling causality test procedure. The findings suggested that there was a statistically significant relationship between exports and economic growth in several Sub-Saharan countries. However, the causal linkages between exports and economic growth in these countries were found to be weak and unstable. These empirical results have some notable policy implications.     

ROBUST UTILITY MAXIMIZATION WITH LÉVY PROCESSES

We study a robust portfolio optimization problem under model uncertainty for an investor with logarithmic or power utility. The uncertainty is specified by a set of possible Lévy triplets, that is, possible instantaneous drift, volatility, and jump characteristics of the price process. We show that an optimal investment strategy exists and compute it in semi‐closed form. Moreover, we provide a saddle point analysis describing a worst‐case model.     

Market development and market efficiency: evidence based on nonlinear panel unit root tests

This study tests the weak form market efficiency of 32 European stock markets. Utilizing monthly data from June 2006 to June 2017, six different, newly developed nonlinear panel root tests were applied in three different groups of European markets: Frontier, Emerging and Developed. The results show that there is a meaningful relationship between different levels of economic development and the weak form market efficiency. Considering the nonlinear structure of the stock market indices, use of linear models might lead to wrong conclusions regarding market efficiency. Using several nonlinear panel root tests, the results of this study shed more light on the true data generating process of the stock market indices and more appropriately model market efficiency.     

Existence of a calibrated regime switching local volatility model

By Gyöngy's theorem, a local and stochastic volatility model is calibrated to the market prices of all European call options with positive maturities and strikes if its local volatility (LV) function is equal to the ratio of the Dupire LV function over the root conditional mean square of the stochastic volatility factor given the spot value. This leads to a stochastic differential equation (SDE) nonlinear in the sense of McKean. Particle methods based on a kernel approximation of the conditional expectation, as presented in Guyon and Henry‐Labordère [Risk Magazine, 25, 92–97], provide an efficient calibration procedure even if some calibration errors may appear when the range of the stochastic volatility factor is very large. But so far, no global existence result is available for the SDE nonlinear in the sense of McKean. When the stochastic volatility factor is a jump process taking finitely many values and with jump intensities depending on the spot level, we prove existence of a solution to the associated Fokker–Planck equation under the condition that the range of the squared stochastic volatility factor is not too large. We then deduce existence to the calibrated model by extending the results in Figalli [Journal of Functional Analysis, 254(1), 109–153].     

The Relationship between Interest Rates and Inflation: Examining the Fisher Effect in China

This study revisits the Fisher effect using a different empirical method that considers a potential nonlinear relationship between interest rates (treasury bond rates) and inflation in China. The rising uncertainty and asymmetric information in financial markets between bond holders and bond issuers suggest such a potential nonlinear relationship. To this aim, we apply Shin et al.’s (2014) nonlinear autoregressive distributed lag (NARDL) model with asymmetric dynamic multipliers for the sample period 2002M7–2018M4. The empirical findings reveal symmetric and asymmetric partial Fisher effects for all sample bond rates in China. Furthermore, we find that 20-year bond rates experience the lowest partial Fisher effect.     

Rank tests for price convergence in Australian beverage markets

This article examines the price convergence of beverage products within Australia in order to assess the efficacy of intranational cross-border movements of products under the Australia’s Mutual Recognition Agreement. Since the cointegrating relationship between product prices may not be exact or linear, we adopt the rank tests for analysis which do not require prior knowledge and specification of the linear or nonlinear functional form. Our results validate the price convergence of all beverage products within Australia, with the exception of a few regions in the milk market. Furthermore, a subset of the cointegration relationships exhibits nonlinear long-run price co-movements.     

The Russian option: Finite horizon

We show that the optimal stopping boundary for the Russian option with finite horizon can be characterized as the unique solution of a nonlinear integral equation arising from the early exercise premium representation (an explicit formula for the arbitrage-free price in terms of the optimal stopping boundary having a clear economic interpretation). The results obtained stand in a complete parallel with the best known results on the American put option with finite horizon. The key argument in the proof relies upon a local time-space formula.Received: March 2004, Mathematics Subject Classification (2000): 91B28, 35R35, 45G10, 60G40, 60J60JEL Classification: G13Goran Peskir: Centre for Analytical Finance (funded by the Danish Social Science Research Council) and Network in Mathematical Physics and Stochastics (funded by the Danish National Research Foundation).The first draft of the present paper has been completed in September 2002. I am indebted to Albert Shiryaev for useful comments.