Closure (topology)

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Revision as of 22:26, 16 September 2007 by imported>Jitse Niesen (subject/verb agreement)
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In mathematics, the closure of a subset A of a topological space X is the set union of A and all its limit points in X. It is usually denoted by . Other equivalent definitions of the closure of A are as the smallest closed set in X containing A, or the intersection of all closed sets in X containing A.