Index form equations in quintic fields

István Gaál; Kálmán Győry

Acta Arithmetica (1999)

  • Volume: 89, Issue: 4, page 379-396
  • ISSN: 0065-1036

Abstract

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The problem of determining power integral bases in algebraic number fields is equivalent to solving the corresponding index form equations. As is known (cf. Győry [25]), every index form equation can be reduced to an equation system consisting of unit equations in two variables over the normal closure of the original field. However, the unit rank of the normal closure is usually too large for practical use. In a recent paper Győry [27] succeeded in reducing index form equations to systems of unit equations in which the unknown units are elements of unit groups generated by much fewer generators. On the other hand, Wildanger [32] worked out an efficient enumeration algorithm that makes it feasible to solve unit equations even if the rank of the unit group is ten. Combining these developments we describe an algorithm to solve completely index form equations in quintic fields. The method is illustrated by numerical examples: we computed all power integral bases in totally real quintic fields with Galois group S₅.

How to cite

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István Gaál, and Kálmán Győry. "Index form equations in quintic fields." Acta Arithmetica 89.4 (1999): 379-396. <http://eudml.org/doc/207277>.

@article{IstvánGaál1999,
abstract = {The problem of determining power integral bases in algebraic number fields is equivalent to solving the corresponding index form equations. As is known (cf. Győry [25]), every index form equation can be reduced to an equation system consisting of unit equations in two variables over the normal closure of the original field. However, the unit rank of the normal closure is usually too large for practical use. In a recent paper Győry [27] succeeded in reducing index form equations to systems of unit equations in which the unknown units are elements of unit groups generated by much fewer generators. On the other hand, Wildanger [32] worked out an efficient enumeration algorithm that makes it feasible to solve unit equations even if the rank of the unit group is ten. Combining these developments we describe an algorithm to solve completely index form equations in quintic fields. The method is illustrated by numerical examples: we computed all power integral bases in totally real quintic fields with Galois group S₅.},
author = {István Gaál, Kálmán Győry},
journal = {Acta Arithmetica},
keywords = {index form equations; power integral bases; computer resolution of diophantine equations; unit equations; quintic fields},
language = {eng},
number = {4},
pages = {379-396},
title = {Index form equations in quintic fields},
url = {http://eudml.org/doc/207277},
volume = {89},
year = {1999},
}

TY - JOUR
AU - István Gaál
AU - Kálmán Győry
TI - Index form equations in quintic fields
JO - Acta Arithmetica
PY - 1999
VL - 89
IS - 4
SP - 379
EP - 396
AB - The problem of determining power integral bases in algebraic number fields is equivalent to solving the corresponding index form equations. As is known (cf. Győry [25]), every index form equation can be reduced to an equation system consisting of unit equations in two variables over the normal closure of the original field. However, the unit rank of the normal closure is usually too large for practical use. In a recent paper Győry [27] succeeded in reducing index form equations to systems of unit equations in which the unknown units are elements of unit groups generated by much fewer generators. On the other hand, Wildanger [32] worked out an efficient enumeration algorithm that makes it feasible to solve unit equations even if the rank of the unit group is ten. Combining these developments we describe an algorithm to solve completely index form equations in quintic fields. The method is illustrated by numerical examples: we computed all power integral bases in totally real quintic fields with Galois group S₅.
LA - eng
KW - index form equations; power integral bases; computer resolution of diophantine equations; unit equations; quintic fields
UR - http://eudml.org/doc/207277
ER -

References

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