Relevant coherent measures of risk

We introduce and study the _f0$f_0$-relevance property of a coherent measure of risk on a positions vector space with vector ordering. We show that it is equivalent to a special no arbitrage condition on bounded positions spaces. Continuity from below leads to representations of _f0$f_0$-relevant coherent measures of risk based on equivalent functionals in Banach subspaces of the order dual. We define and describe _f0$f_0$-martingales in a lattice, and present a solution to the hedging price problem: the asset price process is an order convergent _f0$f_0$-martingale. Under the _f0$f_0$-relevance hypothesis we study the relationship between worst conditional mean and value at risk.     

The restricted convex risk measures in actuarial solvency

In this article, we propose a class of convex risk measures defined on appropriate wedges of a space of financial positions which denote the cumulative surplus variables created by undertaking risks by either an insurance or a reinsurance company. The form of the wedge which is the domain of such a risk measure expresses the form of the company, and it is a subspace in the case of reinsurance companies and a cone in the case of the insurance companies. The value of such a risk measure on an insurance position denotes the capital that the corresponding company has to receive or to keep in advance so that it will not be exposed to risk due to this position. We prove some dual representation and continuity results being similar to the unrestricted case. Finally, we contribute to a decision theory related to the choice of a numeraire asset when the space in which the positions lie in is reflexive.     

Rank-ordering of risk preferences with conventional and discrete measures

When the functional form of utility is unknown, conventional measures of risk aversion are often approximated by applying a Taylor series expansion to expected utility. This is shown to produce counterintuitive rank-orderings of risk preferences for individuals who are willing to pay equal reservation prices in lotteries with different prizes. Moreover, individuals who are unwilling to participate in favorable lotteries may be incorrectly identified as having a finite aversion to risk. Correct orderings are obtained by applying a discrete measure of relative risk aversion. The contrast between the conventional and discrete measures is illustrated with data from three Dutch surveys.     

A representation of decision by analogy

We give a representation of analogical reasoning in choice under uncertainty. A decision maker is faced with two decision problems, a familiar and a novel one. It is shown that, under assumptions that capture the salience of alignable differences in choice, the decision maker can be construed as choosing between acts in the novel decision problem as if drawing all likelihood information from a multi-valued correspondence between states of the world in the familiar domain and states of the world in the novel domain. The latter is interpreted as an analogy between the two decision problems, and the fuzziness of the analogy is related to revealed ambiguity in the novel decision problem.     

地下商场的火灾危险性分析与预防对策

对地下商场的火灾危险性进行了分析,为使地下商场安全运营,提出了预防地下商场火灾的基本措施及相应对策。     

A reference-dependent representation with subjective tastes

Experimental and empirical evidence documents instances where the presence of an inferior option in a menu increases the attractiveness of the better options from that menu and thus distorts the normative ranking across menus. We analyze the case when in addition to this so called context-effects bias there is also a concern for flexibility, in the spirit of the literature initiated by Kreps (1979) and Dekel et al. (2001). Since the context-effects bias and the desire for flexibility both increase the inclination of a decision maker to choose larger menus, our analysis allows the disentangling of the effect of the behavioral bias from the effect of the rational desire from flexibility. We find a weak condition on the set of ex post preferences under which the two effects are identifiable. We show that our representation is essentially unique. From a methodological viewpoint, our paper provides a novel technique of identifying probabilities on the state space of subjective uncertainty introduced by Dekel et al. (2001) when this state space is infinite. This method renders the infinite state space essentially finite with respect to a certain salient property.     

Coherent risk measures in general economic models and price bubbles

In this article we study coherent risk measures in general economic models where the set of financial positions is an ordered Banach space E$E$ and the safe asset an order unit _x0$x_0$ of E$E$. First we study some properties of risk measures. We show that the set of normalized (with respect to _x0$x_0$) price systems is weak star compact and by using this result we prove a maximum attainment representation theorem which improves the one of Jaschke and Küchler (2001). Also we study how a risk measure changes under different safe assets and we show a kind of equivalence between these risk measures. In the sequel we study subspaces of E$E$ consisting of financial positions of risk greater or equal to zero and we call these subspaces unsure. We find some criteria and we give examples of these subspaces. In the last section, we combine the unsure subspaces with the theory of price-bubbles of Gilles and LeRoy (1992).     

A numerical representation of preferences with intransitive indifference

It is shown that, under certain conditions on a preference relation on a subset X of R^m, there exist real-valued functions u and v on X such that x is preferred to y if and only if u(x)>v(y). This generalises the familiar representation of preferences by a utility function in the case where the preference and indifference relations are transitive. The continuity of the functions u and v is also discussed.     

A special representation of a sufficient randomization kernel

Summary A recent paper byKumar/Pathak [1977] contains two examples showing how—in the presence of a boundedly complete sufficient statistic—a randomization kernel can be obtained which yields a random variable equivalent to the original one.It is the purpose of this note to present a simple general theorem containing these examples as special cases. The essential assumption is that the observation can be expressed by a pair of stochastically independent statistics, one of which is ancillary.     

Rates of almost sure convergence of plug-in estimates for distortion risk measures

In this article, we consider plug-in estimates for distortion risk measures as for instance the Value-at-Risk, the Expected Shortfall or the Wang transform. We allow for fairly general estimates of the underlying unknown distribution function (beyond the classical empirical distribution function) to be plugged in the risk measure. We establish strong consistency of the estimates, we investigate the rate of almost sure convergence, and we study the small sample behavior by means of simulations.     

Optimal portfolio selection via conditional convex risk measures on L p

We consider conditional convex risk measures on L ^p and show their robust representation in a standard way. Such measures are used as evaluation functionals for optimal portfolio selection in a Black&Scholes setting. We study this problem focusing on the conditional Average Value at Risk and the conditional entropic risk measure and compare the respective optimizers.     

A numerical representation of semiorders on a countable set

Let be a semiorder on a countable setX and letx⁰ y if and only if either there existsx withxxy or there existsx withxxy. Then ⁰ is a preference relation with transitive indifference, which can be represented by a utility functionf of the usual sort. It is well known that is represented by a pair of real-valued functionsu, v, in the sense thatxy if and only ifu(x)>v(y). We prove that there exists a pair of functionsu, v, representing , such thatu+v is the utility function which represents in the usual sense. Moreover it is easily seen that, for such a pair of functionsu, v, we havex⁰ y if and only if eitheru(x)>u(y) or (u(x)=u(y) andv(x)>v(y)).

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Sommario Consideriamo unsemiordine su un insiemeX numerabile e poniamox⁰ y se e solo se esistex tale chexxy, oppure esistex tale chexxy. In questo caso ⁰ è unordine debole, che può essere rappresentato da una funzione di utilitàf nel senso usuale. D'altra parte è rappresentato da una coppia di funzioniu, v, nel senso chexy se e solo seu(x)>v(y). In questo lavoro si prova che ammette una rappresentazioneu, v tale chex⁰ y se e solo seu(x)+v(x)>u(y)+v(y). Si dimostra altresì che, con riguardo ad una siffatta rappresentazioneu, v di , riescex⁰ y se e solo seu(x)>u(y) oppure (u(x)=u(y) ed anchev(x)>v(y)).

     

A utility representation theorem with weaker continuity condition

We prove that a mixture continuous preference relation has a utility representation if its domain is a convex subset of a finite dimensional vector space. Our condition on the domain of a preference relation is stronger than Eilenberg (1941) and Debreu (1959, 1964), but our condition on the continuity of a preference relation is strictly weaker than the usual continuity assumed by them.     

An empirical examination of the effectiveness of dollar-cost averaging using downside risk performance measures

Some studies find the dollar-cost averaging investment strategy to be sub-optimal using a traditional Sharpe ratio performance ranking metric. Using both the Sortino ratio and the Upside Potential ratio, we empirically test four investment strategies for alternative asset investments. We find the relative ranking of dollar-cost averaging remains inferior to alternative investment strategies. (JEL G1, G11, N2)     

A comparative analysis of measures of social homogeneity

Social homogeneity refers to the degree to which the preferences of individuals in a society tend to be alike. A number of studies have been conducted to determine whether or not a relationship exists between various measures of social homogeneity and the probability that a Condorcet winner exists. In this study, it is shown that a strong general relationship of this type does not exist for measures of social homogeneity which account only for the proportions of individuals with various preference rankings. That is, for measures which account for these proportions but not for the preference rankings to which they are assigned. Profile specific measures of homogeneity do account for the preference rankings to which the proportions of voters are assigned. A much stronger relationship exists between profile specific measures of homogeneity and the probability that a Condorcet winner exists than for non-profile specific measures. In particular, Kendall's Coefficient of Condordance is shown to dominate twenty other measures of social homogeneity in terms of the strength of its relationship to the probability that a Condorcet winner exists.     

浅析上市公司担保的特点、风险及防范措施

文章对近来上市公司的对外担保进行了统计特征分析,总结出了近年来上市公司的对外担保的特点,并且探讨了上市公司的担保风险,最后提出了防范上市公司担保风险的对策与建议。     

技术性贸易壁垒的演变趋势及其应对措施

技术性贸易壁垒(简称TBP)在政策上具有双重性,促进了其在当代国际贸易中的运用和发展,出现了一些新的趋势特征,对国际经济贸易影响日益增强。文章提出针对TBT的新变化应采取相应的对策。     

The predictive power of fund ratings with a novel approach using uncertainty measures to analyzing risk

Using two approaches to panel data, Granger causality analysis with semi-asymptotic tests, and a structural approach based on entropies measured on sequences of multiperiod ratings and returns, we specify the relationship between a fund’s performance and both Morningstar and Europerformance ratings. We conclude on the Europerformance agency’s forecasting ability for the Luxembourg funds, and the Morningstar agency for the French funds. Indeed, we find two groups of funds depending on their domiciliation and appropriated rating. The results of this paper have implications for the management of fund portfolios, and the structural approach, more robust to our data, must be a first process for forecast models on the basis of similar funds, minor uncertainty or risk measure, and appropriated rating.