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On the first sign change of Fourier coefficients of cusp forms. (English) Zbl 1441.11093

Summary: Let \(f\) be a nonzero cusp form of even integral weight \(k \geqslant 2\) on the Hecke congruence subgroup \(\Gamma_0(N)\) with \(N\) squarefree. Suppose that the normalized Fourier coefficients \(\lambda_f(n)\) of \(f\) are real. We prove that the first sign change of \(\lambda_f(n)\) occurs in the range \(n \ll(k N)^{2 + \varepsilon}\). This improves upon the earlier result of Y. Choie and W. Kohnen [Am. J. Math. 131, No. 2, 517–543 (2009; Zbl 1254.11044)].

MSC:

11F30 Fourier coefficients of automorphic forms
11F12 Automorphic forms, one variable

Citations:

Zbl 1254.11044
Full Text: DOI

References:

[1] Choie, Y.; Gun, S.; Kohnen, W., An explicit bound for the first sign change of the Fourier coefficients, Int. Math. Res. Not. IMRN, 12, 3782-3792 (2015) · Zbl 1333.11041
[2] Choie, Y.; Kohnen, W., The first sign change of Fourier coefficients of cusp forms, Amer. J. Math., 131, 2, 517-543 (2009) · Zbl 1254.11044
[3] Gun, S.; Sengupta, J., Sign changes of Fourier coefficients of Siegel cusp forms of degree two on Hecke congruence subgroups, Int. J. Number Theory, 13, 10, 2597-2625 (2017) · Zbl 1428.11079
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