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The Additive Characters of the Witt Ring of an Algebraic Number Field

Published online by Cambridge University Press:  20 November 2018

P. E. Conner
Affiliation:
Louisiana State University, Baton Rouge, Louisiana
Noriko Yui
Affiliation:
Queen's University, Kingston, Ontario
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For an algebraic number field K there is a similarity between the additive characters defined on the Witt ring W(K), [20], [11], [17], [14, p. 131], and the local root numbers associated to a real orthogonal representation of the absolute Galois group of K, [18], [5]. Using results of Deligne and of Serre, [16], we shall derive in (5.3) a formula expressing the value, at a prime in K, of the additive character on a Witt class in terms of the rank modulo 2, the stable Hasse-Witt invariant and the local root number associated to the real quadratic character defined by the square class of the discriminant. Thus we are able to separate out the contributions made to the value of the additive character by each of the standard Witt class invariants.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1988

References

1. Blij, F. Van der, An invariant of quadratic forms mod 8, Indag. Math. 21 (1959), 291293.Google Scholar
2. Bruen, A., Jensen, C. U. and Yui, N., Polynomials with Frobenius groups of prime degree as Galois groups II, J. Number Theory 24 (1986), 305359.Google Scholar
3. Cassels, J. W. S., Über die Àquivalenz 2-adischer quadratischer Formen, Comment. Math. Helv. 17(1962), 6164.Google Scholar
4. Conner, P. E. and Perlis, R., A survey of trace forms of algebraic number fields, Series in Pure Math. 2 (World Scientific Publishing Co., Singapore, 1984).CrossRefGoogle Scholar
5. Deligne, P., Les constantes locales de l'équation fonctionnelle de la fonction L d'Artin d'une représentation orthogonale, Invent. Math. 35 (1976), 299316.Google Scholar
6. Feit, W., Some consequences of the classification of finite simple groups, AMS Proc. Symposia in Pure Math. 37 (1980), 175181.Google Scholar
7. Frôhlich, A., Orthogonal representations of Galois groups, Stiefel-Whitney classes and Basse-Witt invariants, Jour. Reine Angew. Math. 360 (1985), 351360.Google Scholar
8. Hasse, H., Number theory, Grundlehren der math. Wissenschaften Bd. 229 (Springer-Verlag, Berlin-Heidelberg-New York, 1980).Google Scholar
9. Jensen, C. U. and Yui, N., Polynomials with D as Galois group, J. Number Theory 15 (1982), 347375.Google Scholar
10. Kahn, B., La deuxième classe de Stiefel-Whitney d'une représentation régulière I, II, C.R. Acad. Se. Paris, Série I 297 (1983), 313316 and (1983), 573–576.Google Scholar
11. Knebusch, M. and Scharlau, W., Quadratische Formen und quadratische Reziprozitdtsgesetzè über algebraischen Zahlkôrpern, Math. Z 121 (1971), 346368.Google Scholar
12. Lang, S., Algebraic number theory (Addison-Wesley Publishing Co., Reading, Massachusetts, 1968).Google Scholar
13. Ledermann, W., An arithmetical property of quadratic forms, Comment. Math. Helv. 33 (1959), 3437.Google Scholar
14. Milnor, J. W. and Husemoeller, D., Symmetric bilinear forms, Ergebnisse der Mathematik 73 (Springer-Verlag, Berlin-Heidelberg-New York, 1973).CrossRefGoogle Scholar
15. O'Meara, O. T., Introduction to quadratic forms, Second Edition, Grundlehren der math. Wissenschaften 117 (Springer-Verlag, Berlin-Heidelberg-New York, 1971).Google Scholar
16. Serre, J.-P., L'invariant de Witt de la Tr(X2), Comment. Math. Helv. 59 (1984), 651676.Google Scholar
17. Scharlau, W., Quadratic reciprocity laws, J. Number Theory 4 (1972), 7897.Google Scholar
18. Tate, J., Local constants, algebraic number fields (Academic Press Inc., New York, 1977)., 89131.Google Scholar
19. Vila, N., Sobre la realitzacio de les extensions contrais del grup alternat com a grup de Galois sobre el cos dels racionals, Thesis Univ. Auton. Barcelone (1983).CrossRefGoogle Scholar
20. Weil, A., Sur certains groupes d'opérateurs unitares, Acta Math. Ill (1964), 143211.Google Scholar