Skip to main content
Log in

Some unexpected phenomena in the Franke filtration of the space of automorphic forms of the general linear group

  • Published:
Israel Journal of Mathematics Aims and scope Submit manuscript

Abstract

In his famous paper [11], J. Franke has defined a certain finite filtration of the space of automorphic forms of a general reductive group, which captures most of its internal representation theory. The purpose of this paper is to provide several concrete examples of yet unexpected phenomena, which occur in the Franke filtration for the general linear group. More precisely, we show that the degenerate Eisenstein series arising from the parabolic subgroups of the same rank are not necessarily contributing to the same quotient of the filtration, and that, even more, the Eisenstein series arising from the parabolic subgroups of higher relative rank may contribute to a deeper quotient of the filtration. These are the first structural counterexamples to an expectation, mentioned in [11].

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. J. Arthur, The L2-Lefschetz numbers of Hecke operators, Inventiones Mathematicae 97 (1989), 257–290.

    Article  MathSciNet  Google Scholar 

  2. J. Arthur, The Endoscopic Classification of Representations, American Mathematical Society Colloquium Publications, Vol. 61, American Mathematical Society, Providence, RI, 2013.

    Google Scholar 

  3. A. Borel, Stable real cohomology of arithmetic groups, Annales Scientifiques de l’École Normale Supérieure 7 (1974), 235–272 (1975).

    Article  MathSciNet  Google Scholar 

  4. A. Borel, Regularization theorems in Lie algebra cohomology. Applications, Duke Mathematical Journal 50 (1983), 605–623.

    Article  MathSciNet  Google Scholar 

  5. A. Borel, Introduction to the cohomology of arithmetic groups, in Lie Groups and Automorphic Forms, AMS/IP Studies in Advanced Mathematics, Vol. 37, American Mathematical Society, Providence, RI, 2006, pp. 51–86.

    Google Scholar 

  6. A. Borel and H. Jacquet, Automorphic forms and automorphic representations, in Automorphic Forms, Representations and L-Functions. Part 1, Proceedings of Symposia in Pure Mathematics, Vol. 33, American Mathematical Society, Providence, RI, 1979, pp. 189–202.

    Chapter  Google Scholar 

  7. A. Borel and N. Wallach, Continuous Cohomology, Discrete Subgroups, and Representations of Reductive Groups, Mathematical Surveys and Monographs, Vol. 67, American Mathematical Society, Providence, RI, 2000.

    Google Scholar 

  8. L. Clozel, Motifs et formes automorphes: applications du principe de fonctorialité, in Automorphic Forms, Shimura varieties, and L-functions. Vol. I (Ann Arbor, MI, 1988), Perspectives in Mathematics, Vol. 10, Academic Press, Boston, MA, 1990, pp. 77–159.

    Google Scholar 

  9. V. G. Drinfel’d, Two theorems on modular curves, Funkcional’nyi Analiz i ego Priloženija 7 (1973), 83–84.

    MathSciNet  Google Scholar 

  10. R. Elkik, Le théorème de Manin–Drinfel’d, Astérisque 183 (1990), 59–67.

    MathSciNet  Google Scholar 

  11. J. Franke, Harmonic analysis in weighted L2-spaces, Annales Scientifiques de l’École Normale Supérieure. 31 (1998), 181–279.

    Article  Google Scholar 

  12. J. Franke and J. Schwermer, A decomposition of spaces of automorphic forms, and the Eisenstein cohomology of arithmetic groups, Mathematische Annalen 311 (1998), 765–790.

    Article  MathSciNet  Google Scholar 

  13. M. Goresky and R. MacPherson, Lefschetz numbers of Hecke correspondences, in The Zeta Functions of Picard Modular Surfaces, Université de Montréal, Montreal, QC, 1992, pp. 465–478.

    Google Scholar 

  14. N. Grbac, The Franke filtration of the spaces of automorphic forms supported in a maximal proper parabolic subgroup, Glasnik Matematički. Serija III 47(67) (2012), 351–372.

    Article  MathSciNet  Google Scholar 

  15. N. Grbac, The Franke filtration of the spaces of automorphic forms on the symplectic group of rank two, Memoirs of the American Mathematical Society, to appear.

  16. N. Grbac and H. Grobner, The residual Eisenstein cohomology of Sp4 over a totally real number field, Transactions of the American Mathematical Society 365 (2013), 5199–5235.

    Article  MathSciNet  Google Scholar 

  17. N. Grbac and J. Schwermer, Eisenstein series for rank one unitary groups and some cohomological applications, Advances in Mathematics 376 (2021), Article no. 107438.

  18. H. Grobner, Residues of Eisenstein series and the automorphic cohomology of reductive groups, Compositio Mathematica 149 (2013), 1061–1090.

    Article  MathSciNet  Google Scholar 

  19. H. Grobner, Smooth-Automorphic Forms and Smooth-Automorphic Representations, Series on Number Theory and its Applications, Vol. 17, World Scientific, Hackensack, NJ, 2023.

    Book  Google Scholar 

  20. H. Grobner and A. Raghuram, On some arithmetic properties of automorphic forms of GLm over a division algebra, International Journal of Number Theory 10 (2014), 963–1013.

    Article  MathSciNet  Google Scholar 

  21. H. Grobner and S. Žunar, On the notion of the parabolic and the cuspidal support of smooth-automorphic forms and smooth-automorphic representations, https://arxiv.org/abs/2108.06369.

  22. M. Hanzer and G. Muić, On the images and poles of degenerate Eisenstein series for \(GL(n,\mathbb{A}_{\mathbb{Q}})\) and GL(n, ℝ), American Journal of Mathematics 137 (2015), 907–951.

    Article  MathSciNet  Google Scholar 

  23. G. Harder, General aspects in the theory of modular symbols, in Seminar on Number Theory, Paris 1981–82 (Paris, 1981/1982), Progress in Mathematics, Vol. 38, Birkhäuser, Boston, MA, 1983, pp. 73–88.

    Google Scholar 

  24. G. Harder, Some results on the Eisenstein cohomology of arithmetic subgroups of GLn, in Cohomology of Arithmetic Groups and Automorphic Forms (Luminy-Marseille, 1989), Lecture Notes in Mathematics, Vol. 1447, Springer, Berlin, 1990, pp. 85–153.

    Chapter  Google Scholar 

  25. H. H. Kim, Automorphic L-functions, in Lectures on Automorphic L-Functions, Fields Institute Monographs, Vol. 20, American Mathematical Society, Providence, RI, 2004, pp. 97–201.

    Google Scholar 

  26. B. Kostant, Lie algebra cohomology and the generalized Borel–Weil theorem, Annals of Mathematics 74 (1961), 329–387.

    Article  MathSciNet  Google Scholar 

  27. R. P. Langlands, On the Functional Equations Satisfied by Eisenstein Series, Lecture Notes in Mathematics, Vol. 544, Springer, Berlin–New York, 1976.

    Google Scholar 

  28. J.-S. Li and J. Schwermer, On the Eisenstein cohomology of arithmetic groups, Duke Mathematical Journal 123 (2004), 141–169.

    Article  MathSciNet  Google Scholar 

  29. S. MacLane, Categories for the Working Mathematician, Graduate Texts in Mathematics, Vol. 5, Springer, New York–Berlin, 1971.

    Google Scholar 

  30. Ju. I. Manin, Parabolic points and zeta functions of modular curves, Izvestiya Akademii Nauk SSSR. Seriya Matematicheskaya 36 (1972), 19–66.

    MathSciNet  Google Scholar 

  31. C. Mœglin and J.-L. Waldspurger, Le spectre résiduel de GL(n), Annales Scientifiques de l’École Normale Supérieure 22 (1989), 605–674.

    Article  MathSciNet  Google Scholar 

  32. C. Mœglin and J.-L. Waldspurger, Spectral Decomposition and Eisenstein Series, Cambridge Tracts in Mathematics, Vol. 113, Cambridge University Press, Cambridge, 1995.

    Google Scholar 

  33. C. P. Mok, Endoscopic classification of representations of quasi-split unitary groups, Memoirs of the American Mathematical Society 235 (2015).

  34. D. A. Vogan, Jr. and G. J. Zuckerman, Unitary representations with nonzero cohomology, Compositio Mathematica 53 (1984), 51–90.

    MathSciNet  Google Scholar 

Download references

Acknowledgement

We would like to thank the anonymous referee for a careful reading of the manuscript, and in particular, for providing the intuition behind the proof of Lemma 4.2.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Neven Grbac.

Additional information

The first-named author is supported by the Croatian Science Foundation under the projects HRZZ-IP-2018-01-3628, HRZZ-IP-2019-04-4216 and HRZZ-IP-2022-10-4615. The second-named author is supported by the START-project Y966 and the Stand-Alone-Research project P32333, both sponsored by the Austrian Science Fund (FWF).

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Grbac, N., Grobner, H. Some unexpected phenomena in the Franke filtration of the space of automorphic forms of the general linear group. Isr. J. Math. (2024). https://doi.org/10.1007/s11856-024-2625-x

Download citation

  • Received:

  • Revised:

  • Published:

  • DOI: https://doi.org/10.1007/s11856-024-2625-x

Navigation