The equilibrium set of two-player games with complementarities is a sublattice

Summary. I prove that the equilibrium set in a two-player game with complementarities, and totally ordered strategy spaces, is a sublattice of the joint strategy space. Received: May 31, 2001; revised version: October 4, 2002     

The substitutes condition and the lattice structure of the set of stable allocations

In the many-to-one matching model with contracts, I show that there is no restriction on preferences weaker than substitutable preferences which guarantees that the set of stable allocations is a lattice. Thus, when contracts are not substitutes, removing agents from the economy may decrease the payoffs to existing agents on both sides of the market.     

Optimal risk transfer and investment policies based upon stochastic differential utilities

This paper addresses the stochastic differential utility (SDU) version of the issue raised by Barrieu and El Karoui (Quantitative Finance, 2:181–188, 2002a) in which optimal risk transfer from a bank to an investor, realized by transacting well-designed derivatives written on relevant illiquid assets, was␣mainly studied in two cases with and without an available financial market. From a stochastic maximum principle as described in Yong and Zhou (Stochastic controls: Hamiltonian systems and HJB equations. Springer-Verlag, New York, 1999) we shall derive necessary and sufficient conditions for optimality in several SDU-based maximization problems. It is also shown that the optimal risk transfer, consumptions, investment policies of both agents are characterized by a forward–backward stochastic differential equation (FBSDE) system.     

基于概念格的产品创新知识配置研究

利用形式概念分析方法构建出产品创新知识配置的概念格模型,以Chrome吧获取浏览器产品开发信息和知识配置过程为例,基于虚拟社区取得用户需求知识,并结合1996-2013年国内浏览器相关专利数据,建立了基于虚拟社区用户需求知识的浏览器创新知识配置模型。     

Strategic interaction and dynamics under endogenous time preference

This paper presents a strategic growth model with endogenous time preference. Due to the potential lack of concavity and the differentiability of the value functions associated with each agent’s problem, we employ the theory of monotone comparative statics and supermodular games based on order and monotonicity properties on lattices. In particular, we provide the sufficient conditions of supermodularity for dynamic games with open-loop strategies based on two fundamental elements: the ability to order elements in the strategy space of the agents and the strategic complementarity which implies upward sloping best responses. The supermodular game structure of the model lets us provide the existence and the monotonicity results on the greatest and the least equilibria. We sharpen these results by showing the differentiability of the value function and the uniqueness of the best response correspondences almost everywhere and show that the stationary state Nash equilibria tend to be symmetric. Finally, we numerically analyze to what extent the strategic complementarity inherent in agents’ strategies can alter the convergence results that could have emerged under a single agent optimal growth model. In particular, we show that the initially rich can pull the poor out of the poverty trap even when sustaining a higher level of steady state capital stock for itself.     

Designer path independent choice functions

Summary. This paper provides an algorithm for the construction of all PICFs on a finite set of alternatives, V, designed by an a priori given set I of initial choices as well as the determination of whether the initial set I is consistent with path independence. The algorithm is based on a new characterization result for path independent choice functions (PICF) on finite domains and uses that characterization as the basis of the algorithm. The characterization result identifies two properties of a partition of the Boolean algebra as necessary and sufficient for a choice function C to be a PICF: (i): For every subset A of V the set is an interval in the Boolean algebra 2 ^V . (ii): If A/B is an interval in the Boolean algebra such that C(A) = C(B) and if M/N is an upper transpose of A/B then C(M) = C(N). The algorithm proceeds by expanding on the implications of these two properties.Received: 5 November 2003, Revised: 20 July 2004, JEL Classification Numbers: D00, D70.     

Spatial Dependence,Housing Submarkets,and House Price Prediction

This paper compares alternative methods of controlling for the spatial dependence of house prices in a mass appraisal context. Explicit modeling of the error structure is characterized as a relatively fluid approach to defining housing submarkets. This approach allows the relevant submarket to vary from house to house and for transactions involving other dwellings in each submarket to have varying impacts depending on distance. We conclude that—for our Auckland, New Zealand, data—the gains in accuracy from including submarket variables in an ordinary least squares specification are greater than any benefits from using geostatistical or lattice methods. This conclusion is of practical importance, as a hedonic model with submarket dummy variables is substantially easier to implement than spatial statistical methods.

Comparative Statics for the Consumer Problem

This paper studies comparative statics in the consumer utlity maximization problem with two goods. The analysis can be global, and it allows for indivisibilities, discrete changes, and non-binding budget constraints. It does not rely either on topological or convexity assumptions. Instead, it uses lattice programming techniques. The conditions derived are superextremal variant properties on the utility function, in appropriately constructed lattices on the consumption set. Sufficient conditions are given for one or both goods to be normal, for one to be inferior, and for some cases of price effects, using what are called value orders and lattices.     

建材交易的期权管理模式探究

涉及大宗建材交易,交易双方往往都要承担很大的价格风险,不同时点风险又过于集中到交易一方,基于期权理论提出建材交易的期权管理模式作为解决该问题的新思路。首先论证解决建材价格波动问题的必要性,接着介绍建材交易期权管理模式的框架构成,最后借助期权定价模型和Crystal Ball软件来计算建材期权的理论价格,并进行了实例验证。运作该模式的目的是统筹管理一定时域、地域上的建材交易业务,来实现交易双方持续、协调和稳定的发展。