The tail index is an important parameter to decide the degree of heaviness of the tail of a distribution.

尾部指标是决定分布尾部轻重的一个重要参数。

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The estimation of tail index for regular variation heavy-tailed distributions aroused our concern, many scholars proposed several methods, but all of them have some disadvantages.

正规变化重尾分布的尾部指数的估计方法有很多种，但都不同程度地存在一定的局限性。

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There is a wide variation around the index return which at the tail can be devastating.

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