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Cubic fields and Mordell curves. (English) Zbl 1202.11034

Zhang, Wenpeng (ed.) et al., Number theory. Tradition and modernization. Papers from the 3rd China-Japan seminar on number theory, Xi’an, China, February 12–16, 2004. New York, NY: Springer (ISBN 978-0-387-30414-4/hbk). Developments in Mathematics 15, 175-183 (2006).
In the present article, the author considers elliptic curves over \(\mathbb{Q}\) given by \(w^3=P(u)\), where \(P(u)\) is a monic irreducible cubic polynomial over \(\mathbb{Q}\), with the distinguished point on the projective curve given by the unique rational point at infinity in the above model. First, a bijection between the rational points on the curve and the set \({\mathcal{W}}(\xi)=\{q\xi+r | \text{Norm}_{K\big/\mathbb{Q}}(q\xi+r) = 1,q,r\in \mathbb{Q}\}\) is established, where \(\xi\in K\) is a root of \(P(u)\) in a cubic number field. The rest of the article is devoted to a case by case study of these elliptic curves. They are all either isomorphic to pure cubic twists of the Fermat cubic, and that case is not considered further in this paper, or to a curve with Weierstrass model \(y^2 = x^3-B^2(B+3)\), \(B\in \mathbb{Q}^\times\). For the curves in the latter family, all but two have rank at least 1 and a point of infinite order is exhibited on each of them.
For the entire collection see [Zbl 1131.11004].

MSC:

11G05 Elliptic curves over global fields
11R16 Cubic and quartic extensions

Citations:

Zbl 1080.14520
Full Text: DOI