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基于凸优化的有效做市&与在线学习的联系

Efficient Market Making via Convex Optimization & Connection to Online Learning
课程网址: http://videolectures.net/nipsworkshops2011_wortman_vaughan_convex...  
主讲教师: Jenn Wortman Vaughan
开课单位: 加州大学洛杉矶分校
开课时间: 2012-01-25
课程语种: 英语
中文简介:
预测市场是旨在聚合信息的金融市场。为促进交易,预测市场通常由自动化做市商操作。做市商交易一系列证券,​​其收益取决于未来事件的结果。例如,当且仅当民主党赢得2012年美国总统大选时,做市商可能会提供支付1美元的证券。认为民主党获胜概率为p的风险中性交易者应该愿意以低于p的任何价格购买该证券,或以高于p的任何价格出售。然后,当前的市场价格可以被视为交易者对民主党赢得大选的可能性的集体估计。事实证明,基于市场的估计在各个领域都是准确的,包括商业,娱乐和政治。然而,当结果的数量非常大时,在整个结果空间上运行简单的预测市场通常是不可行的。我们提出了在组合或无限状态或结果空间上设计证券市场的一般框架。我们的框架使得能够设计计算有效的市场,以适应具有有限收益的任意但相对较小的证券空间。我们证明,任何满足一组直观条件的市场都必须通过凸成本函数定价证券,凸函数函数是通过共轭二元性构造的。我们的框架不是直接处理指数大或无限的结果空间,而是需要优化凸壳。通过将自动做市的问题减少到凸优化,存在许多有效算法,我们得到了一系列针对各种问题的新的多项式时间定价机制。我们的框架也为市场设计和机器学习之间的关系提供了新的见解。特别是,我们表明,为在线线性优化开发的工具与我们为选择定价机制而构建的工具非常相似。这是相当令人惊讶的,因为在线环境中学习的问题在语义上与预测市场中的证券定价问题完全不同:学习算法接收损失并选择权重,而做市商管理交易和设定价格。我们展示了虽然这两个框架具有非常不同的语义,但它们在非常强烈的意义上具有几乎相同的语法。
课程简介: A prediction market is a financial market designed to aggregate information. To facilitate trades, prediction markets are often operated by automated market makers. The market maker trades a set of securities with payoffs that depend on the outcome of a future event. For example, the market maker might offer a security that will pay off $1 if and only if a Democrat wins the 2012 US presidential election. A risk neutral trader who believes that the probability of a Democrat winning is p should be willing to purchase this security at any price below p, or sell it at any price above p. The current market price can then be viewed as the traders’ collective estimate of how likely it is that a Democrat will win the election. Market-based estimates have proved to be accurate in a variety of domains, including business, entertainment, and politics. However, when the number of outcomes is very large, it is generally infeasible to run a simple prediction market over the full outcome space. We propose a general framework for the design of securities markets over combinatorial or infinite state or outcome spaces. Our framework enables the design of computationally efficient markets tailored to an arbitrary, yet relatively small, space of securities with bounded payoff. We prove that any market satisfying a set of intuitive conditions must price securities via a convex cost function, which is constructed via conjugate duality. Rather than deal with an exponentially large or infinite outcome space directly, our framework only requires optimization over a convex hull. By reducing the problem of automated market making to convex optimization, where many efficient algorithms exist, we arrive at a range of new polynomial-time pricing mechanisms for various problems. Our framework also provides new insights into the relationship between market design and machine learning. In particular, we show that the tools that have been developed for online linear optimization are strikingly similar to those we have constructed for selecting pricing mechanisms. This is rather surprising, as the problem of learning in an online environment is semantically quite distinct from the problem of pricing securities in a prediction market: a learning algorithm receives losses and selects weights whereas a market maker manages trades and sets prices. We show that although the two frameworks have very different semantics, they have nearly identical syntax in a very strong sense.
关 键 词: 金融市场; 预测市场; 凸函数
课程来源: 视频讲座网
最后编审: 2019-09-08:lxf
阅读次数: 65