5 papers
Hasse norm principle for extensions of prime squared degree
Yasuhiro Oki
We give an equivalent condition for the validity of the Hasse norm principle for finite separable extensions of prime squared degree of global fields. Our theorem recovers the resu…
The rationality problem for multinorm one tori, II
Sumito Hasegawa, Kazuki Kanai, Yasuhiro Oki
We investigate the stable and retract rationality of multinorm one tori associated to finite {é}tale algebras. Our results are organized according to the greatest common divisor $…
The rationality problem for multinorm one tori
Sumito Hasegawa, Kazuki Kanai, Yasuhiro Oki
In this paper, we study the rationality problem for multinorm one tori, a natural generalization of norm one tori. For multinorm one tori that split over finite Galois extensions w…
The Hasse norm principle for some extensions of degree having square-free prime factors
Yasuhiro Oki
We determine the structure of the obstruction group of the Hasse norm principle for a finite separable extension of a global field of degree , where has a square-free…
Cohomological properties of multinorm-one tori
Pei-Xin Liang, Yasuhiro Oki, Chia-Fu Yu
In this paper we investigate the Tate--Shafarevich group Sha^1(k, T) of a multinorm-one torus over a global field . We establish a few functorial maps among cohomology group…