Fintie point sets in a Hausdorff space are closed.

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SUMMARY

The discussion centers on the proof that finite point sets in a Hausdorff space are closed, as established in Munkres' text. The user demonstrates an understanding of the concept by proving that one-point sets are closed using the method of showing that the complement is open. The response confirms that this alternative approach is valid, reinforcing the principles of topology in Hausdorff spaces.

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  • Understanding of Hausdorff spaces in topology
  • Familiarity with the concept of closure and open sets
  • Knowledge of one-point sets and their properties
  • Experience with proofs in mathematical analysis
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  • Study the properties of closed sets in topological spaces
  • Explore Munkres' "Topology" for deeper insights on Hausdorff spaces
  • Learn about the concept of neighborhoods and their role in topology
  • Investigate the implications of finite sets in various topological contexts
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jmjlt88
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This may seem like a silly question, but I'll ask it anyways. :)

In the Munkres text, he proves this by showing that one-point sets are closed, which I completely understand why it follows that finite point sets are closed. He does so by showing that the arbitrary one-point set {x0} equals its own closure, and therefore closed (which, again I completely understand). Now, before I read a proof, I like to see try it myself. When I did it, I also proved that one-point sets are closed, but I did so by showing X-{x0} is open. I did this by noting that for each x in X-{x0}, there is disjoint neighborhoods Ux and V containing x and x0 respectively. I then showed that X-{X0} is the union of all Ux, and it therefore open.

My question is, does this approach work as well? Thank you!
 
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Yes, your approach works.
 

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