On the resolution of index form equations in quartic number fields
✍ Scribed by István Gaál; Attila Pethő; Michael Pohst
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 570 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0747-7171
No coin nor oath required. For personal study only.
✦ Synopsis
In this paper we reduce the problem of solving index form equations in quartic number fields (K) to the resolution of a cubic equation (F(u, v)=i) and a corresponding system of quadratic equations (Q_{1}(x, y, z)=u, Q_{2}(x, y, z)=v), where (F) is a binary cubic form and (Q_{1}, Q_{2}) are ternary quadratic forms.
This enables us to develop a fast algorithm for calculating "small" solutions of index form equations in any quartic number field. If, additionally, the field (K) is totally complex we can combine the (t) wo forms to get an equation (T(x, y, z)=T_{0}) with a positive definite quadratic form (T(x, y, z)). Hence, in that case we obtain a fast method for the complete resolution of index form equations.
At the end of the paper we present numerical tables. We computed minimal indices and all elements of minimal index
(i) in all totally real quartic fields with Galois group (A_{4}) and discriminant (<10^{6}(31) fields),
(ii) in the 50 totally real fields with smallest discriminant and Galois group (S_{4}),
(iii) in the (\mathbf{5 0}) quartic fields with mixed signature and smallest absolute discriminant,
(iv) and in all totally complex quartic fields with discriminant (<10^{6}) and Galois group (A_{4}) (90 fields) or (S_{4}) ( 44122 fields).
📜 SIMILAR VOLUMES
We give an efficient algorithm for the resolution of index form equations, especially for determining power integral bases, in sextic fields with an imaginary quadratic subfield. The method reduces the problem to the resolution of a cubic relative Thue equation over the quadratic subfield. At the en
Let Q 1 , Q 2 # Z[X, Y, Z] be two ternary quadratic forms and u 1 , u 2 # Z. In this paper we consider the problem of solving the system of equations (1) Q 2 (x, y, z)=u 2 in x, y, z # Z with gcd(x, y, z)=1. According to Mordell [12] the coprime solutions of can be presented by finitely many expr
We describe an efficient algorithm for solving index form equations in number fields of degree 9 which are composites of cubic fields with coprime discriminants. We develop the algorithm in detail for the case of complex cubic fields, but the main steps of the procedure are also applicable for other