How do elements really factor in $\mathbb{Z}[\sqrt{-5}]$?
History and Overview
2019-05-03 v2 Number Theory
Abstract
Most undergraduate level abstract algebra texts use as an example of an integral domain which is not a unique factorization domain (or UFD) by exhibiting two distinct irreducible factorizations of a nonzero element. But such a brief example, which requires merely an understanding of basic norms, only scratches the surface of how elements actually factor in this ring of algebraic integers. We offer here an interactive framework which shows that while is not a UFD, it does satisfy a slightly weaker factorization condition, known as half-factoriality. The arguments involved revolve around the Fundamental Theorem of Ideal Theory in algebraic number fields.
Cite
@article{arxiv.1711.10842,
title = {How do elements really factor in $\mathbb{Z}[\sqrt{-5}]$?},
author = {Scott T. Chapman and Felix Gotti and Marly Gotti},
journal= {arXiv preprint arXiv:1711.10842},
year = {2019}
}
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25 pages