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Hilbert's Seventeenth Problem and Hyperelliptic Curves

Published online by Cambridge University Press:  01 February 2010

Valéry Mahé
Affiliation:
School of Mathematics, University of East Anglia, Norwich NR4 7TJ, United Kingdom, v.mahe@uea.ac.uk

Abstract

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This article deals with a constructive aspect of Hilbert's seventeenth problem: producing a collection of real polynomials in two variables, of degree 8 in one variable, which are positive but are not sums of three squares of rational fractions.

To do this we use a reformulation of this problem in terms of hyperelliptic curves due to Huisman and Mahé and we follow a method of Cassels, Ellison and Pfister which involves the computation of a Mordell–Weil rank over ℝ(x).

Type
Research Article
Copyright
Copyright © London Mathematical Society 2008

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