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Singularities and vanishing cycles in number theory over function fields

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Abstract

This article is an overview of the vanishing cycles method in number theory over function fields. We first explain how this works in detail in a toy example and then give three examples which are relevant to current research. The focus will be a general explanation of which sorts of problems this method can be applied to.

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References

  1. Andrade, J.C., Keating, J.P.: Conjectures for the integral moments and ratios of \(L\)-functions over function fields. J. Number Theory 142, 102–148 (2014)

    Article  MathSciNet  Google Scholar 

  2. Beilionson, A., Bernstein, J., Deligne, P., Gabber, O.: Fascieaux Pervers, Astérisque Société Mathématique de France. Paris 100 (1982)

  3. Burgess, D.A.: On character sums and primitive roots. Proc. Lond. Math. Soc. 3, 179–192 (1962)

    Article  MathSciNet  Google Scholar 

  4. Cohen, D.C., Dimka, A., Orlik, P.: Nonresonance conditions for arrangements. Ann. Inst. Four. 53, 1883–1896 (2003)

    Article  MathSciNet  Google Scholar 

  5. Church, T., Ellenberg, J.S., Farb, B.: Representation stability in cohomology and asymptotics for families of varieties over finite fields. Contemp. Math. 620, 1–54 (2014)

    Article  MathSciNet  Google Scholar 

  6. Conrey, J.B., Farmer, D.W., Keating, J.P., Rubinstein, M.O., Snaith, N.C.: Integral moments of \(L\)-functions. Proc. Lond. Math. Soc. 91, 33–104 (2005)

    Article  MathSciNet  Google Scholar 

  7. Deligne, P.: With the collaboration of Boutot, J.F. Grothendieck, A., Illusie, L., Verdier, J.L., Séminaire de Géométrie Algébrique du Bous Marie SGA 4\(\frac{1}{2}\)—Cohomologie Etale, Lecture Notes in Mathematics 569

  8. Deligne, P., Katz, N. (eds.): Séminaire de Géométrie Algébrique du Bois Marie—1967–1969—Groupes de monodromie en géométrie algébrique—(SGA 7)—vol. 2, Lecture Notes in Mathematics (in French), Vol. 340. Springer

  9. Duke, W.: Hyperbolic distribution problems and half-integral weight Maass forms. Invent. Math. 92, 73–90 (1988)

    Article  MathSciNet  Google Scholar 

  10. Ellenberg, J.S.: Arizona Winter School 2014 Course Notes: Geometric Analytic Number Theory. http://swc.math.arizona.edu/aws/2014/2014EllenbergNotes.pdf (2014)

  11. Ellenberg, J., Venkatesh, A., Westerland, C.: Homological stability for Hurwitz spaces and the Cohen–Lenstra conjecture over function fields. Ann. Math. 183, 729–786 (2016)

    Article  MathSciNet  Google Scholar 

  12. Ellenberg, J., Westerland, C., Tran, T.: Fox–Neuwirth–Fuks cells, quantum shuffle algebras, and Malle’s conjecture for function fields. arXiv:1701.04541 (2017)

  13. Frietag, E., Kiehl, R.: Etale cohomology and the Weil conjecture. In: A Series of Modern Surveys in Mathematics (1988)

  14. Fu, L.: Etale cohomology theory. In: Nankai Tracts in Mathematics, vol. 13 (2015)

  15. Goresky, M., Macpherson, R.: Intersection homology theory. Topology 19, 135–162 (1980)

    Article  MathSciNet  Google Scholar 

  16. Grothendieck, A. (eds.): Séminaire de Géométrie Algébrique du Bois Marie—1967-1969—Groupes de monodromie en géométrie algébrique—(SGA 7)—vol. 2, Lecture Notes in Mathematics (in French), Vol. 288. Springer

  17. Hast, D.R., Matei, V.: Higher moments of arithmetic functions in short intervals: a geometric perspective. Int. Math. Res. Not. 2019(21), 6554–6584 (2019)

  18. Hooley, C.: On the number of points on a complete intersection over a finite field. J. Number Theory 38(3), 338–358 (1991)

    Article  MathSciNet  Google Scholar 

  19. Katz, N.M.: Sums of Betti numbers in arbitrary characteristic. Finite Fields Appl. 7, 29–44 (2001)

    Article  MathSciNet  Google Scholar 

  20. Katz, N.M.: On a question of Keating and Rudnick about primitive Dirichlet characters with squarefree conductor. IMRN 2013, 3221–3249 (2013)

    Article  MathSciNet  Google Scholar 

  21. Khayutin, I.: Joint equidistribution of CM points. Ann. Math. 189, 145–276 (2019)

    Article  MathSciNet  Google Scholar 

  22. Lang, S.: Algebraic groups over finite fields. Am. J. Math. 78, 555–563 (1956)

    Article  MathSciNet  Google Scholar 

  23. Massey, D.: Numerical invariants of perverse sheaves. Duke Math. J. 73, 307–369 (1994)

    Article  MathSciNet  Google Scholar 

  24. Massey, D.: Notes on perverse sheaves and vanishing cycles. arXiv:math/9908107 (1999)

  25. Michel, P., Venkatesh, A.: Equidistribution, \(L\)-functions and Ergodic theory: on some problems of Yu. V. Linnik (unpublished version). http://math.stanford.edu/~akshay/research/linnik.pdf (2006)

  26. Pólya, G.: Ueber die Verteilung der quadratischen Reste und Nichtreste. Nachr. Akad. Wiss. Goettingen, pp. 21–29 (1918)

  27. Saito, T.: The characteristic cycle and the singular support of a constructible sheaf. Invent. Math. 207, 597–695 (2017)

    Article  MathSciNet  Google Scholar 

  28. Sawin, W.: Square-root cancellation for sums of factorization functions over short intervals in function fields. arXiv:1809.015137 (2018)

  29. Sawin, W.: Bounds for the stalks of perverse sheaves in characteristic p and a conjecture of Shende and Tsimerman (with an appendix by J. Tisimerman). arXiv:1907.04850 (2019)

  30. Sawin, W.: Square-root cancellation for sums of arithmetic functions in squarefree progressions over function fields (in preparation)

  31. Sawin, W., Shusterman, M.: On the Chowla and twin primes conjectures over \({\mathbb{F}}_q[T]\). arXiv:1808.04001 (2019)

  32. Shende, V., Tsimerman, J.: Equidistribution in \(\operatorname{Bun}_2({\mathbb{P}}^1)\). Duke Math. J. 166, 3461–3504 (2017)

    Article  MathSciNet  Google Scholar 

  33. Vinogradov, I.M.: Sur la distribution des residus and nonresidus des puissances. J. Soc. Phys. Math. Univ. Permi, pp. 18–28 (2018)

  34. Weil, A.: On some exponential sums. Proc. Natl. Acad. Sci. 34, 204–207 (1948)

    Article  MathSciNet  Google Scholar 

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Acknowledgements

This article was written while the author served as a Clay Research Fellow. I would like to thank Johan de Jong, Jordan Ellenberg, Philippe Michel, and (especially) the anonymous referee for many helpful comments on earlier versions of this paper.

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Correspondence to Will Sawin.

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Sawin, W. Singularities and vanishing cycles in number theory over function fields. Res Math Sci 7, 12 (2020). https://doi.org/10.1007/s40687-020-00210-x

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