arXiv subjects
Publications and source records attributed to Masanari Kida.
We investigate finite group structures that yield complex irreducible characters induced simultaneously from two or more distinct subgroups. When such a group is realized as the Galois group of a Galois extension of number fields, this phenomenon implies that multiple subfields share the same Artin $L$-function.
In their recent paper, Rosen, Takeyama, Tasaka, and Yamamoto constructed recurrent sequences providing a decomposition law of primes in a Galois extension. In this paper, we reconstruct their sequences via representation theory of finite groups and obtain an explicit description of the sequences.
We redefine a multiplicative group structure on the set of equivalence classes of rational sequences satisfying a fixed linear recurrence of degree two, which was defined by R. R. Laxton in his paper "On groups of linear recurrences I" published in Duke Math. 36, 721--736 (1969). In the article, he also defined some natural subgroups of the group, and determined the structures of their quotient groups. However, he did not study the whole group itself. Nothing has been known about the structure of Laxton's whole group and its interpretation. The aims of this paper are to redefine Laxton's group in a natural way and determine the structure of the whole group itself, which clarifies Laxton's results on the quotient groups. According to our formulation by algebraic number theory method, we can simplify the proof of Laxton's results. Our definition also gives a natural interpretation of Laxton's results, and makes us possible to use the group to show various properties of such sequences.
We develop a general classification theory for Brumer's dihedral quintic polynomials by means of Kummer theory arising from certain elliptic curves. We also give a similar theory for cubic polynomials.