人民币无法替代美元

靠低端制造业获得的外汇储备远不足以支撑中国坐上“一战”后美国的位置。     

并购重组“更好的时代”来临了吗？

今年以来,在市场化改革不断推进的背景下,我国企业的并购重组步伐加快。清科研究中心的报告显示,2014年上半年中国企业共完成并购案例784起,较2013年同期上涨79.8%,中国并购市场共涉及交易金额510.23美元,同比回升19%。     

危机应对术

回忆去年的情况，用一段比较流行的话来说，基本上眼睛一闭一睁，发现世界变了，箭头的方向变了，指标的颜色变了，公司的形势变了，经营业绩变了。     

美元“跳水”不易

无论从市场杠杆还是政治因素来看,美元在中短期都会走出一波上升行情,但从长期来看,无论跳水还是飙升,似乎都不太可能。     

放大镜下看美元

美国总统奥巴马2010年9月8日就美国经济形势发表讲话,提出了降低失业率、刺激经济发展的相关举措,资金规模约为1000亿美元。其中包括：对企业进一步减税以帮助创造就业;延长针对中产阶级的减税期限;扩大对清洁能源的研发及投资;加大基础设施建设以及针对商业活动减税等。这些政策的辐射范围远不止美国本土企业,同时也将对中国企业产生显性或隐性的深远影响。     

逃离危机

石油是国民经济的“血液”，一个“贫血”的国家经济如何发展？当原油价格突破每桶200美元时，新一轮的能源危机是否会诱发经济大崩溃？当危机爆发时，企业又该如何应对？     

三次数学危机

噢,怎么可能呢？数学危机？神奇的、几乎可以说是万能的数学,怎么可能会有危机呢？真是难以置信!嗨,那就跟我一起走进数学的历史,亲眼见证这一切吧!     

数学家长寿吗？

一般认为,数学的特点是抽象、简洁、优美、逻辑,所以学习数学会使人更加聪明、理性、逻辑性强等．但是,文[1]的作者在提到数学家瓦尔登时,发出“长寿的数学家真多”的感慨．长寿的数学家真的很多吗？如果（不）长寿,（不）长寿的原因是什么？数学家长寿和数学职业有关系吗？为了回答这些问题,我们还是先来看看历史上数学家的寿命概况吧．     

你明白吗？

解了大量的题为什么“不开窍”？弗里德曼指出：主要原因是“获得了答案”后,缺乏“分析”解题过程．     

越南危机传染路径

如果越南最终陷入货币危机，那么可能通过什么途径传染？传染哪些国家和地区？这是我们需要关注的问题。我们不能忽视越南危机传染的风险。     

国际黄金期价与美元指数交互关系的多重分形分析

由于美元是国际黄金市场的主要标价货币,其币值的变化与国际金价的波动密切相关。本文利用多重分形分析法研究纽约商品交易所黄金期货价格数据与美元指数之间的交互相关性及两者的内部结构特征,并使用分形特征统计量度量市场风险大小。结果表明,虽然黄金期价和美元指数的收益率序列之间存在长期的负相关关系,但这种负相关关系是非线性动态变化的,具有多重分形特征,多重分形强度是时变性的,意味着市场风险大小随时间的不同而改变。     

Partial Latin Squares Are Avoidable

A square array is avoidable if for each set of n symbols there is an n × n Latin square on these symbols which differs from the array in every cell. The main result of this paper is that for m ≥ 2 any partial Latin square of order 4m − 1 is avoidable, thus concluding the proof that any partial Latin square of order at least 4 is avoidable.     

Avoidable algebraic subsets of Euclidean space

Fix an integer and consider real -dimensional . A partition of avoids the polynomial , where each is an -tuple of variables, if there is no set of the partition which contains distinct such that . The polynomial is avoidable if some countable partition avoids it. The avoidable polynomials are studied here. The polynomial is an especially interesting example of an avoidable one. We find (1) a countable partition which avoids every avoidable polynomial over , and (2) a characterization of the avoidable polynomials. An important feature is that both the ``master' partition in (1) and the characterization in (2) depend on the cardinality of .

     

Avoidable structures, I: Finite ordered sets, semilattices and lattices

We find all finite unavoidable ordered sets, finite unavoidable semilattices and finite unavoidable lattices. While working on this paper, the second and third authors were supported by US NSF grant DMS-0604065. The second author was also supported by the Grant Agency of the Czech Republic, grant #201/05/0002 and by the institutional grant MSM0021620839 financed by MSMT.     

Avoidable structures, II: Finite distributive lattices and nicely structured ordered sets

Let be the ordered set of isomorphism types of finite distributive lattices, where the ordering is by embeddability. We characterize the order ideals in that are well-quasi-ordered by embeddability, and thus characterize the members of that belong to at least one infinite anti-chain in . While working on this paper, the second and third authors were supported by US NSF grant DMS-0604065. The second author was also supported by the Grant Agency of the Czech Republic, grant #201/05/0002 and by the institutional grant MSM0021620839 financed by MSMT.     

Dollar vs. percentage markup pricing schemes under a dominant retailer

We investigate two very common pricing schemes for a Stackelberg-dominant retailer: percentage-markup and dollar-markup. We show that when a dominant retailer switches from dollar to percentage markup, the channel’s “overall pie” and the retailer’s “pie-piece” are both enlarged. In contrast, the manufacturer will be forced to levy a lower wholesale price, thus receiving a smaller pie-piece despite the larger pie. The preceding statements hold regardless of whether the demand is deterministic or stochastic. However, the effects of switching to percentage markup on the retail price and sales volume will depend not only on whether the demand is stochastic, but also on the assumed demand-curve shape and on whether demand stochasticity is “additive” or “multiplicative”. Besides presenting a comprehensive set of answers on the comparative performance of dollar- and percentagemarkups, our results also highlight the often overlooked importance of choosing between: (i) dollar- and percentage-markup; and (ii) the formats of the assumed stochasticity and demand curves.     

Crisis and risk dependencies

The knowledge of the multivariate stochastic dependence between the returns of asset classes is of importance for many finance applications, such as asset allocation or risk management. By means of goodness-of-fit tests, we analyze for a multitude of portfolios consisting of different asset classes whether the stochastic dependence between the portfolios’ constituents can be adequately described by multivariate versions of some standard parametric copula functions. Furthermore, we test whether the stochastic dependence between the returns of different asset classes has changed during the recent financial crisis. The main findings are: First, whether a specific copula assumption can be rejected or not, crucially depends on the asset class and the time period considered. Second, different goodness-of-fit tests for copulas can yield very different results and these differences can vary for different asset classes and for different tested copulas. Third, even when using various goodness-of-fit tests for copulas, it is not always possible to differentiate between various copula assumptions. Fourth, during the financial crisis, copula assumptions are more frequently rejected. However, the results also raise some concerns over the suitability of goodness-of-fit tests for copulas as a diagnostic tool for identifying stressed risk dependencies.