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**blbl****Member**- Registered: 2010-05-25
- Posts: 4

Define τ⊂ P(ℝ) as follows:

τ={φ}∪{u⊆ℝ:{-π,π}⊆u} .

prove that τ is a topology on ℝ .

*Last edited by blbl (2010-05-26 02:49:34)*

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

What is phi?

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

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