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December 15th, 2007, 08:11 AM   #1
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Isomorphism

There is a well defined function (phi) : F ----> F given by the formula (phi)(a+b(sqrt)2) = a-b(sqrt)2 Prove that phi is an isomorphism from F to F.
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December 15th, 2007, 08:34 AM   #2
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Re: Isomorphism

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Originally Posted by just17b
There is a well defined function (phi) : F ----> F given by the formula (phi)(a+b(sqrt)2) = a-b(sqrt)2 Prove that phi is an isomorphism from F to F.
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You don't write what is F, you don't say what have you done with this problem, you don't mention why is phi well defined...
This is not serious

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Tonio
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December 15th, 2007, 02:51 PM   #3
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your right, sorry F is all a+b(sqrt)2 with a and b rational and F is a subfield of R.
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December 18th, 2007, 06:58 AM   #4
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What progress have you made so far?
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December 18th, 2007, 07:57 AM   #5
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not very much, i always have trouble starting
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