No Arbitrage in Discrete Time Under Portfolio Constraints

In frictionless securities markets, the characterization of the no-arbitrage condition by the existence of equivalent martingale measures in discrete time is known as the fundamental theorem of asset pricing. In the presence of convex constraints on the trading strategies, we extend this theorem under a closedness condition and a nondegeneracy assumption. We then provide connections with the superreplication problem solved in Föllmer and Kramkov (1997).     

在线促销限制对消费者购买决策的影响研究——基于精细加工可能性视角

文章基于精细加工可能性理论探究了在线购物情景中不同促销限制类型（时间限制和数量限制）对消费者购买决策行为的影响。通过2（产品涉入度：高vs低）×2（限制类型：限时vs限量）的组间因子实验设计进行了实证研究,结果发现：在线促销情境下,促销限制对消费者购买决策的影响受到消费者产品涉入度的调节。当产品涉入度高时,消费者偏好时间限制促销,购买意向更高,感知控制感起了中介作用。当产品涉入度低时,偏好数量限制促销,购买意向更高,感知稀缺性起了中介作用。文章丰富了促销理论和消费者购买决策理论,同时为商家进行有效的在线促销提供了直接指导。     

A note on the long rate in factor models of the term structure

In this paper, we consider factor models of the term structure based on a Brownian filtration. We show that the existence of a nondeterministic long rate in a factor model of the term structure implies, as a consequence of the Dybvig–Ingersoll–Ross theorem, that the model has an equivalent representation in which one of the state variables is nondecreasing. For two‐dimensional factor models, we prove moreover that if the long rate is nondeterministic, the yield curve flattens out, and the factor process is asymptotically nondeterministic, then the term structure is unbounded. Finally, we provide an explicit example of a three‐dimensional affine factor model with a nondeterministic yet finite long rate in which the volatility of the factor process does not vanish over time.     

宁夏城市体系结构优化战略研究

城市体系是经济区的基本骨骼系统,是区域社会经济发展到一定阶段的产物,是城市带动区域最有效的组织形式,研究宁夏的结构体系具有理论和实践双重价值。综合运用分形理论、城市经济基础研究法等方法,从城市群的等级规模结构、职能结构、空间结构三个方面确定宁夏的结构特征。从而发现当前限制宁夏城市体系进一步发展的诸多因素,并有针对性地提出宁夏城市体系结构优化的政策建议。     

CONVEX RISK MEASURES FOR GOOD DEAL BOUNDS

We study convex risk measures describing the upper and lower bounds of a good deal bound, which is a subinterval of a no‐arbitrage pricing bound. We call such a convex risk measure a good deal valuation and give a set of equivalent conditions for its existence in terms of market. A good deal valuation is characterized by several equivalent properties and in particular, we see that a convex risk measure is a good deal valuation only if it is given as a risk indifference price. An application to shortfall risk measure is given. In addition, we show that the no‐free‐lunch (NFL) condition is equivalent to the existence of a relevant convex risk measure, which is a good deal valuation. The relevance turns out to be a condition for a good deal valuation to be reasonable. Further, we investigate conditions under which any good deal valuation is relevant.     

ARBITRAGE BOUNDS FOR PRICES OF WEIGHTED VARIANCE SWAPS

We develop a theory of robust pricing and hedging of a weighted variance swap given market prices for a finite number of co‐maturing put options. We assume the put option prices do not admit arbitrage and deduce no‐arbitrage bounds on the weighted variance swap along with super‐ and sub‐replicating strategies that enforce them. We find that market quotes for variance swaps are surprisingly close to the model‐free lower bounds we determine. We solve the problem by transforming it into an analogous question for a European option with a convex payoff. The lower bound becomes a problem in semi‐infinite linear programming which we solve in detail. The upper bound is explicit. We work in a model‐independent and probability‐free setup. In particular, we use and extend Föllmer's pathwise stochastic calculus. Appropriate notions of arbitrage and admissibility are introduced. This allows us to establish the usual hedging relation between the variance swap and the “log contract” and similar connections for weighted variance swaps. Our results take the form of a FTAP: we show that the absence of (weak) arbitrage is equivalent to the existence of a classical model which reproduces the observed prices via risk‐neutral expectations of discounted payoffs.     

Turbo码的Taylor-Log_MAP译码算法

以Turbo码基本理论和算法为基础,依据无线信息传输的实际要求和Taylor级数的基 本原理,提出了一种Turbo码的Taylor-Log-MAP高效译码算法。该算法对基本的Log-MAP 算法中K运算利用Taylor级数进行展开,针对实际的信道需求对展开式进行截断,实现了Tur bo码 的最佳译码。与传统的对数域最大后验概率译码算法相比,该算法基本保持了优良的译码 性能,同时避免了复杂的对数运算,减小了运算量。仿真结果表明,与现 有的RS码性能相比,使用Turbo码可以获取5 dB的信噪比增益。     

On the pricing of forward starting options in Heston’s model on stochastic volatility

We consider the problem of pricing European forward starting options in the presence of stochastic volatility. By performing a change of measure using the asset price at the time of strike determination as a numeraire, we derive a closed-form solution within Hestons stochastic volatility framework applying distribution properties of the volatility process. In this paper we develop a new and more suitable formula for pricing forward starting options. This formula allows to cover the smile effects observed in a Black-Scholes environment, in which the extreme exposure of forward starting options to volatility changes is ignored.Received: July 2004, Mathematics Subject Classification (2000): 91B28, 60G44, 60H30, 60E10JEL Classification: G13It is a pleasure to thank the anonymous referee for his valuable comments and suggestions on this paper. Furthermore, we would like to thank Holger Kraft, University of Kaiserslautern, and Alexander Giese, HypoVereinsbank AG Munich, for fruitful discussions and suggestions.     

2012年5月银行问市场运行报告

2012年5月,银行间市场整体平稳运行,主要特点是：市场资金面宽松,货币市场利率持续走低;银行间国债收益率曲线整体下移,利率互换成交曲线也出现明显下移;国际市场美元指数飙升,人民币对美元汇率显著走§5,人民币对欧元汇率破八,汇率盘中波动和升贬预期较为稳定;外汇衍生品成交活跃,市场份额进一步上升。     

2011年1季度银行间市场运行报告

2011年1季度,银行间市场运行平稳,交易量继续稳步增长。其主要特点是：货币市场资金面前紧后松,短期利率先扬后抑,较季初明显回落;银行间国债指数大幅上扬,现券交易集中于中短期品种;美元兑人民币中间价屡创新高,保持较快升值速度,非美货币即期交易显著活跃;IRS交易量较去年同期明显放大,互换利率走高后回落,外汇衍生品市场交易稳定增长,境内外价差缩小。