Note on the ring of integers of a Kummer extension of prime degree. IV
Ichimura, Humio
Proc. Japan Acad. Ser. A Math. Sci., Tome 77 (2001) no. 10, p. 92-94 / Harvested from Project Euclid
Kawamoto [5, 6] proved that for any prime number $p$ and any $a \in \mathbf{Q}^{\times}$, the cyclic extenstion $\mathbf{Q}(\zeta_p, a^{1/p}) / \mathbf{Q}(\zeta_p)$ has a normal integral basis (NIB) if it is tame. We show that this property is peculier to the rationals $\mathbf{Q}$. Namely, we show that for a number field $K$ with $K \neq \mathbf{Q}$, there exist infinitely many pairs $(p, a)$ of a prime number $p$ and $a \in K^{\times}$ for which $K(\zeta_p, a^{1/p}) / K(\zeta_p)$ is tame but has no NIB. Our result is an analogue of the theorem of Greither et al. [3] on Hilbert-Speiser number fields.
Publié le : 2001-06-14
Classification:  Normal integral basis,  Kummer extension of prime degree,  11R33
@article{1148479942,
     author = {Ichimura, Humio},
     title = {Note on the ring of integers of a Kummer extension of prime degree. IV},
     journal = {Proc. Japan Acad. Ser. A Math. Sci.},
     volume = {77},
     number = {10},
     year = {2001},
     pages = { 92-94},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1148479942}
}
Ichimura, Humio. Note on the ring of integers of a Kummer extension of prime degree. IV. Proc. Japan Acad. Ser. A Math. Sci., Tome 77 (2001) no. 10, pp.  92-94. http://gdmltest.u-ga.fr/item/1148479942/