How would you prove it's not a P.I.D. by using I?
Letbe an ideal of
. Prove that I is not a principal ideal of
.
I've been trying this for a long time... and I'm just saying okay it has this form, and then I multiply it by (a+bsqrt(-5)) and this happens... but I keep getting so many terms, that I can't find a contradiction. Please help!