#### Binary quadratic forms and ray class groups

Cited 2 time in Cited 0 time in
• Hit : 169
Let K be an imaginary quadratic field different from $\open{Q}(\sqrt {-1})$ and $\open{Q}(\sqrt {-3})$. For a positive integer N, let K-N be the ray class field of K modulo $N {\cal O}_K$. By using the congruence subgroup +/- Gamma(1)(N) of SL2(DOUBLE-STRUCK CAPITAL Z), we construct an extended form class group whose operation is basically the Dirichlet composition, and explicitly show that this group is isomorphic to the Galois group Gal(K-N/K). We also present an algorithm to find all distinct form classes and show how to multiply two form classes. As an application, we describe Gal(K-N(ab)/K) in terms of these extended form class groups for which K-N(ab) is the maximal abelian extension of K unramified outside prime ideals dividing NOK.
Publisher
CAMBRIDGE UNIV PRESS
Issue Date
2020-04
Language
English
Article Type
Article
Citation

PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS, v.150, no.2, pp.695 - 720

ISSN
0308-2105
DOI
10.1017/prm.2018.163
URI
http://hdl.handle.net/10203/274031
Appears in Collection
MA-Journal Papers(저널논문)
Files in This Item
There are no files associated with this item.
##### This item is cited by other documents in WoS
 ⊙ Detail Information in WoSⓡ Click to see ⊙ Cited 2 items in WoS Click to see citing articles in