# Homework Help: Euchlidean Domain

1. Jan 16, 2006

### ElDavidas

I know this is a physics forum but I've got a quick question about a Euchlidean domain:

Assuming that $1 - \sqrt {-7}$and $2$ are irreduclible, explain why$Z[-7]$ is not a euchlidean domain?

This is a pure maths question and I've asked questions about other pure maths courses and got decent answers.

Thanks

2. Jan 16, 2006

### Muzza

There is no h in Euclidean.

If Z[-7] were Euclidean, then in particular all irreducible elements would be prime. This leads to a contradiction.

3. Jan 16, 2006

### matt grime

Try multiplying 1-sqrt(-7) by its complex conjugate too.