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Thread: Set in R^2 which is neither open nor closed.

  1. November 3rd 2010, 08:53 PM #1
    osodud
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    Question Set in R^2 which is neither open nor closed.

    Can you mention a set in R^2 which is neither open nor closed.

    Thanks
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  2. November 3rd 2010, 09:35 PM #2
    Failure
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    Quote Originally Posted by osodud View Post
    Can you mention a set in R^2 which is neither open nor closed.

    Thanks
    Let's try a really simple one: \{(x,0)\in\mathbb{R}^2\mid x\in \;]0,1[\}
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  3. November 3rd 2010, 11:46 PM #3
    CaptainBlack
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    Quote Originally Posted by osodud View Post
    Can you mention a set in R^2 which is neither open nor closed.

    Thanks
    [a,b[ \times ]c,d] , with a,b,c,d \in \mathbb{R} and a<b, c<d

    CB
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