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A norm residue map for central extensions of an algebraic number field

Published online by Cambridge University Press:  22 January 2016

Yoshiomi Furuta*
Affiliation:
Department of Mathematics, Kanazawa University, Marunouchi, Kanazawa 920, Japan
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Let K be a finite Galois extension of an algebraic number field k with G = Gal (K/k), and M be a Galois extension of k containing K. We denote by resp. the genus field resp. the central class field of K with respect to M/k. By definition, the field is the composite of K and the maximal abelian extension over k contained in M. The field is the maximal Galois extension of k contained in M satisfying the condition that the Galois group over K is contained in the center of that over k. Then it is well known that Gal is isomorphic to a factor group of the Schur multiplicator H-3(G, Z), and is isomorphic to H-3(G, Z) when M is sufficiently large. In this case we call M abundant for K/k (See Heider [3, § 4] and Miyake [6, Theorem 5]).

Type
Research Article
Copyright
Copyright © Editorial Board of Nagoya Mathematical Journal 1984

References

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