Some Results on Weak and Strong Tail Dependence Coefficients for Means of Copulas
نویسندگان
چکیده
Copulas represent the dependence structure of multivariate distributions in a natural way. In order to generate new copulas from given ones, several proposals found its way into statistical literature. One simple approach is to consider convex-combinations (i.e. weighted arithmetic means) of two or more copulas. Similarly, one might consider weighted geometric means. Consider, for instance, the Spearman copula, defined as the geometric mean of the maximum and the independence copula. In general, it is not known whether weighted geometric means of copulas produce copulas, again. However, applying a recent result of Liebscher (2006), we show that every weighted geometric mean of extreme-value copulas produces again an extreme-value copula. The second contribution of this paper is to calculate extremal dependence measures (e.g. weak and strong tail dependence coefficients) for (weighted) geometric and arithmetic means of two copulas.
منابع مشابه
Tail dependence for weighted mean of two copula function
In this paper, we study the properties of power weighted means, arithmetic, geometry and harmonic for two copulas.
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