Unit indices of some imaginary composite quadratic fields

Mikihito Hirabayashi

Vol. 164 (1994), No. 1, 87–104

DOI: 10.2140/pjm.1994.164.87

Abstract

Let K be an imaginary abelian number field of type (2, 2 , 2, 2) not containing the 8th cyclotomic field. Using the fundamental units of real quadratic subfields of K, we give a necessary and sufficient condition for the unit index Q_K of K to be equal to 2.

Mathematical Subject Classification 2000

Primary: 11R27

Secondary: 11R20

Milestones

Received: 30 July 1991

Published: 1 May 1994