Euclidean domains with no multiplicative norms
Caleb J. Dastrup, Pace P. Nielsen
TL;DR
The paper constructs a concrete Euclidean domain R that admits no multiplicative Euclidean norm to any compatibly well-ordered monoid, and hence no multiplicative norm into the usual ordered real numbers. The core method is a transfinite, iterative construction that freely adjoins prime factorizations while preserving unique factorization, culminating in R_infty and a localization R in which the Euclidean division can be forced to fail for multiplicative norms. A key technical ingredient is a rank-based analysis showing that certain remainders necessarily split into at least two primes, contradicting multiplicative monotonicity arguments, while an explicit N-valued norm is still defined to demonstrate R remains Euclidean. The paper also extends the construction to rule out broader monotonicity properties and discusses implications for the existence of multiplicative norms in Euclidean domains, highlighting fundamental limitations in transferring Euclidean structure to multiplicative norm frameworks.
Abstract
We construct a Euclidean domain with no multiplicative Euclidean norm to a compatibly well-ordered monoid, and hence with no multiplicative Euclidean norm to $\mathbb{R}$ (under its usual order). A key step in the proof is showing that the UFD property is preserved when adjoining a free factorization.
