Limits of semistatic trading strategies

We show that pointwise limits of semistatic trading strategies in discrete time are again semistatic strategies. The analysis is carried out in full generality for a two-period model, and under a probabilistic condition for multiperiod, multistock models. Our result contrasts with a counterexample of Acciaio, Larsson, and Schachermayer, and shows that their observation is due to a failure of integrability rather than instability of the semistatic form. Mathematically, our results relate to the decomposability of functions as studied in the context of Schrödinger bridges.     

After Shleifer,who needs Mises?

The demise of socialism in Eastern Europe and the transition to a market economy in China and India marked the end of traditional comparative economics as a field. The debate between capitalism and socialism was settled. The economic calculation argument of Ludwig von Mises seemed no longer relevant. In its place, the new comparative economics (NCE) arose. The NCE focuses on the institutional differences that affect the protection of contract and property rights. The research program of Andrei Shleifer has provided numerous insights into how markets operate. This paper examines the Shleifer-inspired program in comparative economics in light of the economic calculation argument Mises made. Although the recent developments in comparative economics have extended and complemented the contributions of Mises, it has not displaced them. An account of the economic calculation problem is still missing in the new comparative economics.     

一种经济的水渠管道建设策略

本文在光的折射定理的基础上,将费马定理中光程的概念与水库管道建设费用相类比,利用光束在两点间传播时,光程最小的原理,设计了一种使包括公共管道和非公共管道在内的水库灌溉管道线路铺设费用最省的建设方案,并给出了施工方法和施工图纸。该方法通俗易懂,推广性强,可解决其他类似的工程建设中的成本最优问题。