Hostname: page-component-848d4c4894-cjp7w Total loading time: 0 Render date: 2024-07-05T12:06:30.402Z Has data issue: false hasContentIssue false

Note on quadratic forms over the rational field

Published online by Cambridge University Press:  24 October 2008

J. W. S. Cassels
Affiliation:
Trinity CollegeCambridge

Extract

There is perhaps some methodological interest in developing the theory of quadratic forms over the rational field using only the methods of elementary arithmetic. Hitherto it has appeared necessary to use theorems of a fairly deep nature, most often Dirichlet's theorem about the existence of primes in arithmetic progressions (e.g. Minkowski(1), Hasse(2), Dickson(8), Skolem(9), Burton Jones(6)). Skolem(5) uses a weaker form of Dirichlet's theorem which is rather easier to prove and Siegel(4) uses instead the machinery of the Hardy-Littlewood circle method. In this note I indicate how it is possible to develop the theory of quadratic forms over the rationals without using extraneous resources. Pall(10) states that he has also found such a development of the theory but he does not appear to have published it.

Type
Research Notes
Copyright
Copyright © Cambridge Philosophical Society 1959

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)Minkowski, H.Über die Bedingungen unter welchen zwei quadratische Formen mit rationalen Koeffizienten ineinander rational transformiert werden können. J. reine angew. Math. 106 (1890), 278–97 (Werke I, 219–39).Google Scholar
(2)Hasse, H.Über die Darstellbarkeit von Zahlen durch quadratische Fonnen im Körper der rationalen Zahlen. J. reine angew. Math. 152 (1923), 129–48.Google Scholar
(3)Witt, E.Theorie der quadratisehen Formen in beliebigen Körpern. J. reine angew. Math. 176 (1937), 3144.Google Scholar
(4)Siegel, C. L.Equivalence of quadratic forma. Amer. J. Math. 63 (1941), 658–80.CrossRefGoogle Scholar
(5)Skolem, Th.On the diophantine equation ax 2 + by 2 + cz 2dt 2 = 0. Norske Vid. Selsk. Forh. Trondheim, 21, Nr. 19 (1948).Google Scholar
(6)Jones, Burton W.The arithmetical theory of quadratic forms (Buffalo, 1950).CrossRefGoogle Scholar
(7)Eichler, M.Quadratische Formen und orthogonale Oruppen (Berlin, 1952).Google Scholar
(8)Dickson, L. E.Stitdies in the theory of numbers (Chicago, 1930).Google Scholar
(9)Skolem, Th.Diophantische Gleichungen (Berlin, 1938).Google Scholar
(10)Pall, G.The arithmetical invariants of quadratic forms. Bull. Amer. Math. Soc. 51 (1945), 185–97.Google Scholar