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Help 'set' question

  1. Oct 6, 2008 #1
    help!!!!! 'set' question

    Give an example in the set notation of a CLOSED set S in R^2 such that the closure of int S is not equal to S.

    I originally used the set

    s={ (x,y) : 0 <x^2+y^2<1}
    but I just noticed it's not closed set!

    can anyone give me an example?

  2. jcsd
  3. Oct 6, 2008 #2


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    Science Advisor

    Re: help!!!!! 'set' question

    No, but I can suggest something to try: if S is a finite set of points, what is its interior? What is the closure of that?
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