离散时间美式期权套期及停时分析

本文主要证明了在不存在交易成本的市场假设下离散时间美式期权套期价值过程{Vt，Ft，t≥0}为鞅。并且研究了美式期权的停时，分别给出了美式期权的可停时，首停时，最优停时的方程表达式，同时讨论了与他们相关的期望特征，以及研究了美式期权定价问题。     

Average shadow prices in mathematical programming

We develop the concept of average shadow price in mathematical programming. This concept measures the value of resources along a direction in an average sense, in contrast to traditional marginal analysis; it serves as a useful standard price for management decisions about resources, particularly when there are nonconvexities. We give it an economic interpretation. We also develop simple computational schemes for obtaining and improving the bounds of the average shadow prices and illustrate them in two important classes of nonconvex programs: convex maximization problems and mixed integer programs.     

On a class of approximations for closed queueing networks

This paper presents some analytical results concerning an approximation procedure for closed queueing networks. The procedure is well-known and has been found useful for product-form networks where large numbers of queues, jobs or job classes prohibit an exact analysis, as well as for networks which do not possess product-form. The procedure represents the mean sojourn time at a queue as a function of the throughput of the queue, and derives a set of fixed point equations for the throughputs of the various job classes. We begin by showing that under a mild regularity condition the fixed point equations have a unique solution. Then we show that derivatives of performance measures can be readily calculated, and that their simple form provides an interesting insight into capacity allocation in closed queueing networks.This work was supported in part by the Nuffield Foundation     

The super order dual of an ordered vector space and the Riesz-Kantorovich formula

A classical theorem of F. Riesz and L. V. Kantorovich asserts that if is a vector lattice and and are order bounded linear functionals on , then their supremum (least upper bound) exists in and for each it satisfies the so-called Riesz-Kantorovich formula:

Related to the Riesz-Kantorovich formula is the following long-standing problem: If the supremum of two order bounded linear functionals and on an ordered vector space exists, does it then satisfy the Riesz-Kantorovich formula?

In this paper, we introduce an extension of the order dual of an ordered vector space and provide some answers to this long-standing problem. The ideas regarding the Riesz-Kantorovich formula owe their origins to the study of the fundamental theorems of welfare economics and the existence of competitive equilibrium. The techniques introduced here show that the existence of decentralizing prices for efficient allocations is closely related to the above-mentioned problem and to the properties of the Riesz-Kantorovich formula.

     

Risk-minimizing hedging strategies under restricted information: The case of stochastic volatility models observable only at discrete random times

We consider a market where the price of the risky asset follows a stochastic volatility model, but can be observed only at discrete random time points. We determine a local risk minimizing hedging strategy, assuming that the information of the agent is restricted to the observations of the price at its random jump times. Stochastic filtering also comes into play when computing the hedging strategy in the given situation of restricted information.     

Pricing without no-arbitrage condition in discrete time

In a discrete time setting, we study the central problem of giving a fair price to some financial product. This problem has been mostly treated using martingale measures and no-arbitrage conditions. We propose a different approach based on convex duality instead of martingale measures duality: The prices are expressed using Fenchel conjugate and bi-conjugate without using any no-arbitrage condition. The super-hedging problem resolution leads endogenously to a weak no-arbitrage condition called Absence of Instantaneous Profit (AIP) under which prices are finite. We study this condition in detail, propose several characterizations and compare it to the usual no-arbitrage condition NA.     

The valuation of equity warrants in a fractional Brownian environment

In this paper, we discuss the valuation of equity warrants in the geometric fractional Brownian environment based on the equilibrium condition. Using the conditional expectation we present a fractional pricing model for equity warrants and analyze the influence of the Hurst parameter. Then we propose an optimization procedure to obtain the valuation of equity warrants. Some numerical examples are given to demonstrate the pricing results by comparing different pricing models. Furthermore, we provide an empirical study to show how to apply our model in realistic contexts, and these comparative results of different pricing models show that the pricing model proposed in this paper matches the actual price quite well.     

Risky asset allocation and consumption rule in the presence of background risk and insurance markets

This study examines joint decisions regarding risky asset allocation and consumption rate for a representative agent in the presence of background risk and insurance markets. Contrary to the conclusion of the “mutual fund separation theorem”, we show that the optimal risky asset mix will reflect an agent’s risk attitude as long as background risk is not independent of investment risk. This result can, however, be used to solve the “riskyasset allocation puzzle”. We also unveil that optimal insurance to shift background risk is determined through establishing a hedging portfolio against investment risk and is an arrangement maintaining the balance between growth and volatility of expected consumption. Because the optimal insurance we obtain generally leads to a smoother consumption path, it may plausibly explain the “equity premium puzzle” in the financial literature.     

Competitive analysis of online inventory problem with interrelated prices

This paper investigates the online inventory problem with interrelated prices in which a decision of when and how much to replenish must be made in an online fashion even without concrete knowledge of future prices.Four new online models with different price correlations are proposed in this paper,which are the linear-decrease model,the log-decrease model,the logarithmic model and the exponential model.For the first two models,the online algorithms are developed,and as the performance measure of online algorithm,the upper and lower bounds of competitive ratios of the algorithms are derived respectively.For the exponential and logarithmic models,the online algorithms are proposed by the solution of linear programming and the corresponding competitive ratios are analyzed,respectively.Additionally,the algorithm designed for the exponential model is optimal,and the algorithm for the logarithmic model is optimal only under some certain conditions.Moreover,some numerical examples illustrate that the algorithms based on the dprice-conservative strategy are more suitable when the purchase price fluctuates relatively flat.     

Promoting productive mathematical classroom discourse with diverse students

Productive mathematical classroom discourse allows students to concentrate on sense making and reasoning; it allows teachers to reflect on students’ understanding and to stimulate mathematical thinking. The focus of the paper is to describe, through classroom vignettes of two teachers, the importance of including all students in classroom discourse and its influence on students’ mathematical thinking. Each classroom vignette illustrates one of four themes that emerged from the classroom discourse: (a) valuing students’ ideas, (b) exploring students’ answers, (c) incorporating students’ background knowledge, and (d) encouraging student-to-student communication. Recommendations for further research on classroom discourse in diverse settings are offered.