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Consider the ring $R= \mathbb Z [(1+\sqrt-19)/2]$. How do I prove it is not an euclidean domain?

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up vote 6 down vote accepted

This is a fairly messy (at least as far as I know) proof. The most elementary proof I have seen can be found here

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+1 I just spent the last 10 minutes reading the proof in the link. I really like this proof; there is clearly a conceptual idea of considering elements of small norm (which is important for our understanding of a Euclidean domain because the Euclidean algorithm tells us that elements of small norm have nice divisibility properties). Moreover, this conceptual idea is converted into a straightforward proof whose details only involve manipulations with complex numbers. – Amitesh Datta Nov 12 '11 at 10:05
@alex youcis : The link which you have attached is no more accessible now.. If you have saved a copy of that or if you have any other link please post it here... Thank You:) – Praphulla Koushik Oct 10 '13 at 16:35
Here is a link to a file of the same name, I'm not sure it's the same one: – lhf Jun 4 at 14:45

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