Skip to main content
Log in

Weil representations associated with finite quadratic modules

  • Published:
Mathematische Zeitschrift Aims and scope Submit manuscript

Abstract

To any finite quadratic module, that is, a finite abelian group together with a non-degenerate quadratic form, it is possible to associate a representation of \(\mathrm{Mp}_{2}(\mathbb Z )\), the metaplectic cover of the modular group. This representation is usually referred to as a Weil representation and our main result is a general explicit formula for its matrix coefficients. This result completes earlier work by Scheithauer in the case when the representation factors through \(\mathrm{SL}_{2}(\mathbb Z )\). Furthermore, our formula is given in a such a way that it is easy to implement efficiently on a computer.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. Berndt, B.C., Evans, R.J., Williams, K.S.: Gauss and Jacobi Sums. Canadian Mathematical Society Series of Monographs and Advanced Texts. Wiley, New York (1998)

  2. Borcherds, R.E.: Reflection groups of Lorentzian lattices. Duke Math. J. 104(2), 319–366 (2000). doi:10.1215/S0012-7094-00-10424-3

  3. Bruinier, J.H., Strömberg, F.: Computation of harmonic weak Maass forms. Exp. Math. 21(2), 117–131 (2011)

    Article  Google Scholar 

  4. Cassels, J.W.S.: Rational Quadratic Forms. London Mathematical Society Monographs, vol. 13. Academic Press Inc., London (1978)

  5. Conway, J.H., Sloane, N.J.A.: On the classification of integral quadratic forms. In: Conway, J.H., Sloane, N.J.A. (eds.) Sphere Packings, Lattices and Groups, pp. 352–405. Die Grundlehren der mathematischen Wissenschaften, vol. 290, Springer, New York (1999)

  6. Ebeling, W.: Lattices and Codes. Friedrich Vieweg & Sohn, Braunschweig (1994)

    Book  MATH  Google Scholar 

  7. Eichler, M.: Introduction to the Theory of Algebraic Numbers and Functions. Pure and Applied Mathematics, vol. 23. Academic Press, New York (1966)

  8. Gelbart, S.: Weil’s Representation and the Spectrum of the Metaplectic Group. Lecture Notes in Mathematics, vol. 530. Springer, Berlin (1976)

    Google Scholar 

  9. Kloosterman, H.D.: The behaviour of general theta functions under the modular group and the characters of binary modular congruence groups. I, II. Ann. Math. (2) 47, 317–375, 376–447 (1946)

    Google Scholar 

  10. Kubota, T.: Topological covering of SL(2) over a local field. J. Math. Soc. Jpn. 19, 114–121 (1967)

    Article  MathSciNet  MATH  Google Scholar 

  11. Maass, H.: Lectures on Modular Functions of One Complex Variable, 2nd edn. Tata Institute of Fundamental Research Lectures on Mathematics and Physics, vol. 29. Tata Institute of Fundamental Research, Bombay (1983)

  12. Milnor, J., Husemoller, D.: Symmetric Bilinear Forms. Ergebnisse der Mathematik und ihrer Grenzgebiete, Band 73. Springer, New York (1973)

    Book  Google Scholar 

  13. Pfetzer, W.: Die Wirkung der Modulsubstitutionen auf mehrafache Thetareihen zu quadratischen Formen ungerader Variablenzahl. Arch. Math. 4, 448–454 (1953)

    Article  MathSciNet  MATH  Google Scholar 

  14. Ryan, N., Skoruppa, N., Strömberg, F.: Numerical computation of a certain Dirichlet series attached to Siegel modular forms of degree two. Math. Comput. 81(280), 2361–2376 (2012)

    Article  MATH  Google Scholar 

  15. Scheithauer, N.R.: The Weil representation of \({\rm SL}_2({\mathbb{Z}})\) and some applications. Int. Math. Res. Not. 8, 1488–1545 (2009)

    Google Scholar 

  16. Schoeneberg, B.: Das Verhalten von mehrfachen Thetareihen bei Modulsubstitutionen. Math. Ann. 116(1), 511–523 (1939)

    Article  MathSciNet  Google Scholar 

  17. Shimura, G.: On modular forms of half integral weight. Ann. Math. 97, 440–481 (1973)

    Article  MathSciNet  MATH  Google Scholar 

  18. Shintani, T.: On construction of holomorphic cusp forms of half integral weight. Nagoya Math. J. 58, 83–126 (1975)

    MathSciNet  MATH  Google Scholar 

  19. Skoruppa, N.-P.: Finite quadratic modules, Weil representations and vector valued modular forms. (2013, preprint)

  20. Skoruppa, N.P.: Über den Zusammenhang zwischen Jacobiformen und Modulformen halbganzen Gewichts. Bonner Math. Schriften, no. 159. University of Bonn, Bonn (1985)

  21. Stein, W., et al.: Sage mathematics software (Version 5.3). The Sage Development Team (2012). http://www.sagemath.org

  22. Weil, A.: Sur certains groupes d’opérateurs unitaires. Acta Math. 111, 143–211 (1964)

    Article  MathSciNet  MATH  Google Scholar 

Download references

Acknowledgments

I would like to thank Nils Scheithauer for clarifying details of [15], Nils-Peter Skoruppa for sharing thoughts about Weil representations in general, and the manuscript [19], in particular. I would also like to thank Stephan Ehlen for his extensive assistance with proof reading the manuscript and in simplifying Theorem 4.1.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Fredrik Strömberg.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Strömberg, F. Weil representations associated with finite quadratic modules. Math. Z. 275, 509–527 (2013). https://doi.org/10.1007/s00209-013-1145-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00209-013-1145-x

Keywords

Mathematics Subject Classification (2000)

Navigation