A note on the existence of unique equivalent martingale measures in a Markovian setting

Simple sufficient conditions for the existence of a unique equivalent martingale measure are provided. Furthermore, these conditions give us a handle on situations where an equivalent martingale measure cannot exist. The existence of a unique equivalent martingale measure is of relevance to problems in mathematical finance. Two examples of models for which the question of existence was unresolved are studied. By means of our results existence of a unique equivalent measure up to an explosion time is proved.     

Squatting as a transition problem in South Africa

This paper applies principles of transition to land tenure and squatting in South Africa. Political transition in South Africa reassigned political property rights, which produced contestable, and rent‐seeking incentives for squatting as a means to privatize land and redistribute wealth. Government failure to establish and protect private property rights in a squatter camp resulted in common‐pool problems that resisted private and public resolution with consequent rent dissipation and social loss. In response to this retreat from duty, informal agents emerged to claim their own share of the prize. Without enforceable rules of capture, the growth of squatter camps in South Africa will continue. JEL classification: D7, H8, K1, K4, R1, R4.     

瑞风,错位营销决战全国

如何有效进行精准定位,采取与竞争对手定位截然不同的错位营销决胜市场,这是企业面对强大竞争对手实施营销创新最终得以取胜的法宝。     

Differential reporting in Germany - A historical analysis

Based on a contingent perspective of accounting change, this paper reviews the historical development of differential reporting in Germany, by drawing on primary and secondary sources. The main objective of the paper is to shed light on the driving forces and main influential parameters that have shaped the existing differential reporting framework. This historical approach supplies interesting insights for the current discussion on differential reporting in Germany produced by the EU Regulation on the application of International Accounting Standards.     

Vacancies and Rent Dispersion in a Stochastic Search Model with Generalized Tenant Demand

I model imperfect information, derive a downward sloping market demand curve, and explain vacancies in a partial equilibrium model of a rental housing market. Tenants can be completely described by an exogenous demand curve, perhaps arising from differences in income, preferred location, or tastes, and view vacant units based on a stochastic arrival of rental information. Free entry of these landlords induces excess rental housing capacity (equilibrium vacancies). I determine the equilibrium distribution of rents for vacant units, show that this rent distribution may be discontinuous, and explore the equilibrium vacancy rate to changes in exogenous parameters. The resulting characterization of equilibrium distributions of rents may be amenable to econometric modeling exploring the relationship between market rents and vacancies.     

论政府信用失缺及其解决措施

从寻租的角度,主要运用政府官员和民众之间所形成的囚犯困境博弈,分析政府官员腐败产生的机制及原因,并提出相应的解决措施。     

Open access,common property and scarcity rent in fisheries

Open access resources are frequently not managed efficiently, resulting in falling stock levels and a declining income for fishermen. In the late 1970's, the policy response to this problem was the implementation of 200-mile fishing zones, which enabled the European Union to formulate and implement the Common Fisheries Policy, aimed at (among other things) conservation and distribution of available stocks. In Germany, this shift from an open access regime towards a common property regime had favourable outcomes. The trend of falling prices was reversed. The conclusion was that intertemporal efficiency had increased as a result of (inter)governmental policy. Apparently, a wedge was formed between price and marginal harvesting costs, implying that scarcity rent had returned as a component of prices.     

Natural resources, capital accumulation and the resource curse

Early concern by economists for the effect of natural capital on economic growth gave way to complacency and neglect during the nineteenth century. Evidence has emerged, however, that since the 1960s the economic performance of low-income countries has been inversely related to their natural resource wealth. This relationship is not a deterministic one so policy counts. SEEA can help improve the policy and performance of resource-abundant low-income countries by reinforcing the rationale for the sound management of natural resources and also by providing an index of policy sustainability in the form of the net saving rate. This policy index, along with other measures such as a capital fund for sterilizing the rent, initiatives to increase the transparency of rent flows and the rigorous evaluation of alternative uses of additional public sector revenue can improve the efficiency by which natural resource rent is transformed into alternative forms of capital to sustain rising social welfare. Chad and Mauritania provide case studies to illustrate how SEEA and net saving can be used to diagnose policy failure and improve economic performance.     

“Itô's Lemma” and the Bellman Equation for Poisson Processes: An Applied View

Using the Hamilton-Jacobi-Bellman equation, we derive both a Keynes-Ramsey rule and a closed form solution for an optimal consumption-investment problem with labor income. The utility function is unbounded and uncertainty stems from a Poisson process. Our results can be derived because of the proofs presented in the accompanying paper by Sennewald (2006). Additional examples are given which highlight the correct use of the Hamilton-Jacobi-Bellman equation and the change-of-variables formula (sometimes referred to as ``Itô's Lemma'') under Poisson uncertainty.