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Homework Help: Open map

  1. Nov 9, 2011 #1
    What is an example of a continuous function [itex]f:\mathbb{R}\to\mathbb{R}[/itex] such that [itex]f(\mathbb{R})[/itex] is open?
  2. jcsd
  3. Nov 9, 2011 #2


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    Well, [itex]\mathbb{R}[/itex] is open in [itex]\mathbb{R}[/itex], right?
  4. Nov 9, 2011 #3
    So [itex]f(x)=x[/itex] is open
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