The Norm Exponent in Galois Extensions of Number Fields
Hans Opolka · Proceedings of the American Mathematical Society · 1987
The purpose of this note is to provide an upper bound for the exponent of the norm residue group ${k^ * }/\operatorname {Norm}_{K/k}({K^ * })$ of a finite Galois extension $K/k$ of number fields in terms of a certain central extension of $K/k$.