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## Homework Statement

Show [0,1] is not open in ℝ

## Homework Equations

[0,1] is open if and only if ℝ\[0,1] is closed.

## The Attempt at a Solution

ℝ\[0,1] = (-∞,0) U (1,∞), this set is open. Despite the if and only if statement this is enough to say that [0,1] is not open in ℝ.

Is this correct?

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