Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-26T14:50:57.148Z Has data issue: false hasContentIssue false

Cubic forms over algebraic number fields

Published online by Cambridge University Press:  24 October 2008

C. Ryavec
Affiliation:
University of Michigan

Extract

In 1935 Tartakowski (7) proved that, in general, a cubic form in sufficiently many variables with coefficients in an algebraic number field K has a non-trivial zero in that field; and in the case when K is the rational field 57 variables suffice. Here, ‘in general’ means that the coefficients of the form do not lie in a proper subvariety of the coefficient space. Hence, Tartakowski's result holds for almost all cubic forms. Later, Lewis (5) proved that if K is any algebraic number field such that [K: Q] = n, then there exists a function ψ(n) such that every cubic form over K in m ≥ ψ(n) variables has a non-trivial zero in K. His bound, ψ(n), is extremely large; e.g. when K is the rational field, ψ(1) > 500.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1969

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

(1)Cassblls, J. W. S.An introduction to diophantine approximation (Cambridge University Press, 1957).Google Scholar
(2)Davenport, H.Cubic forms in 32 variables. Philos. Trans. Roy. Soc. London, Ser. As 251 (1958), 193232.Google Scholar
(3)Davenport, H.Analytic methods for diphantine equations and inequalities (Ann Arbor: Ann Arbor Publishers, 1962).Google Scholar
(4)Davenport, H.Cubic forms in 16 variables. Proc. Roy. Soc. Ser. A 272 (1963), 285303.Google Scholar
(5)Lewis, D. J.Cubic forms over algebraic number fields. Mathematika 4 (1957), 97101.Google Scholar
(6)Ramanujam, C. P.Cubic forms over algebraic number fields. Proc. Cambridge Philos. Soc. 59 (1963), 683705.Google Scholar
(7)Tartakowski, W.Über Asymtotische Gesetze der ‘Allgemeinen’ Diophantischen Analyse mit vielen Unbekannten. Bulletin of the Academy of Sciences, U.S.S.R. (1935), 483524.Google Scholar