Why is the Class Number of $\Q(\sqrt[3]{11})$ even?.

Authors: Franz Lemmermeyer
Subjects: Number Theory
link: http://arxiv.org/abs/1108.6069
Abstract

In this article we will describe a surprising observation that occurred in
the construction of quadratic unramified extensions of a family of pure cubic
number fields. Attempting to find an explanation will lead us on a magical
mystery tour through the land of pure cubic number fields, Hilbert class
fields, and elliptic curves.