Difference between revisions of "Limit point"
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Revision as of 21:15, 12 February 2015
Contents
Definition
Common form
For a Topological space [math](X,\mathcal{J})[/math], [math]x\in X[/math] is a limit point of [math]A[/math] if every neighborhood of [math]x[/math] has a non-empty intersection with [math]A[/math] that contains some point other than [math]x[/math] itself.
Equivalent form
[math]x[/math] is a limit point of [math]A[/math] if [math]x\in\text{Closure}(A-\{x\})[/math] (you can read about closure here)
TODO: Prove these are the same
Examples
[math]0[/math] is a limit point of [math](0,1)[/math]
Proof using first definition
Is is clear we are talking about the Euclidian metric
