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#1 2009-11-17 23:44:58
- Identity
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- Registered: 2007-04-18
- Posts: 934
What vector space
Give an example of a nonempty subset U of
such that U isclosed under addition and under taking additive inverses (meaning
−u ∈ U whenever u ∈ U), but U is not a subspace of .
I thought the answer would also be a subspace? Why is it not? Thanks
Last edited by Identity (2009-11-17 23:45:58)
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#2 2009-11-18 13:12:45
- gckc123
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- Registered: 2009-10-19
- Posts: 15
Re: What vector space
It is because Z^2 is not closed under multiplication.
Maths is fun!
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#3 2009-11-18 15:23:10
- Identity
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- Registered: 2007-04-18
- Posts: 934
Re: What vector space
Ah ok, thanks
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