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Covering number
Encyclopedia
In mathematics, the ε-covering number of a metric space
(X, d), for some ε > 0, is the minimum number of balls of radius
that are needed to cover X.
A related concept is the ε-packing number which is defined as the maximum number of disjoint balls of radius ε that fit into X.
Metric space
In mathematics, a metric space is a set where a notion of distance between elements of the set is defined.The metric space which most closely corresponds to our intuitive understanding of space is the 3-dimensional Euclidean space...
(X, d), for some ε > 0, is the minimum number of balls of radius
![](http://image.absoluteastronomy.com/images/formulas/4/3/4431329-1.gif)
A related concept is the ε-packing number which is defined as the maximum number of disjoint balls of radius ε that fit into X.