Let KΓk be an extension of degree p 2 over a p-adic number field k with the Galois group G. We study the Galois module structure of the ring O K of integers in K. We determine conditions under which the invariant factors of Kummer orders O K t in O K of two extensions coincide with each other and gi
8-Ranks ofK2of Rings of Integers in Quadratic Number Fields
β Scribed by A. Vazzana
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 156 KB
- Volume
- 76
- Category
- Article
- ISSN
- 0022-314X
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β¦ Synopsis
Let F be a quadratic extension of Q and O F the ring of integers in F. A result of Tate enables one to compute the 2-rank of K 2 O F in terms of the 2-rank of the class group. Formulas for the 4-rank of K 2 O F exist, but are more involved. We give upper and lower bounds on the 8-rank of K 2 O F in terms of the narrow class group. In certain cases the upper and lower bounds agree, and the 8-rank of K 2 O F is exactly the 8-rank of the narrow class group. We then give a family of fields for which this equality holds.
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