Definition: In mathematics, a cofaster is a limit point of a set. A limit point of a set S is a point x in S that has all its neighborhood points lying within some open ball centered at x. A cofaster (or a closed cofaster) in a metric space X is a limit point of the set of all open balls around the point x in X. In other words, a cofaster is a limit point of the intersection of all open balls with center x. For
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