• Dec 8th 2010, 10:44 AM
Samson
Assume $32 = \alpha\beta$ for $\alpha,\beta$ relatively prime quadratic integers in $Q[i]$. It can be shown that $\alpha = \epsilon \gamma^2$ for some unit $\epsilon$ and some quadratic integer $\gamma$ in $Q[i]$.
Well, $32 = 2^5 = (1+i)^5(1-i)^5$. And $1+i,1-i$ are irreducible. But $(1+i)=i(1-i)$. Hence $32 = i(1-i)^{10}$ is the unique expression of $32$ in $\mathbb{Z}[i]$ as a product of irreducibles. Can you finish from there?