## Definition of an outlier in a metric space [closed]

Hello,

Outlier detection is a huge problem with many applications and specifities. But let us be general about that issue and let's consider a metric space. What is in your opinion the best definition of an outlier in this case ?

Guillaume

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the goal is to understand how people define an outlier, what the general idea is behind the technics they use. For example, a very simple definition would be : $\text{a point p is an outlier of a dataset D if its distance from the center of gravity of D is above a threshold \lambda}$. But maybe, someone has a better, more complex definition If mathoverflow is not the good place to ask this question, then where should i ask this ? – GuillaumeThomas Mar 9 2011 at 9:56