Hello, I am trying to think of examples of these. At the moment, I can only think of ( on R ) closed intervals being the union of single-point sets ( infinitely many, the ones inside ).. et c. I also think the cantor set is an example of this.(adsbygoogle = window.adsbygoogle || []).push({});

Are there more "natural" examples? Thank you for sharing.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Examples of infinite/arbitrary unions of closed sets that remain closed.

**Physics Forums | Science Articles, Homework Help, Discussion**