找了好久都没有找到混合韦布尔分布是否有万能近似性质，下面这个算是一点线索，不过看不太懂。
回答1：Ultimately this sounds tautological: just define “well-behaved” as any density that can be approximated, according to some specific metric, arbitrarily closely by mixtures of Weibulls! If you adopt a standard definition of Weibull distributions, though, you will be unable to represent any distribution without non-negative support. Perhaps you intend to include location-shifted Weibulls?
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